Monitoring incomplete heparin reversal and heparin rebound after cardiac surgery.

OBJECTIVES: To assess the incidence of incomplete heparin reversal and heparin rebound after cardiac surgery with cardiopulmonary bypass (CPB) and the ability of the activated coagulation time (ACT) and thromboelastography (TEG) to detect these phenomena. DESIGN: Prospective single-center study. SETTING: University hospital. PARTICIPANTS: Forty-one patients undergoing elective cardiac surgery with CPB and with normal preoperative TEG parameters. INTERVENTIONS: ACT, TEG, and plasma heparin levels were measured in all patients at 5 different times between 20 minutes and 3 hours after protamine administration. The variability of TEG reaction time (R) with and without heparinase (delta-R [DR]) was used to detect the presence of residual heparin. MEASUREMENTS AND MAIN RESULTS: Plasma heparin expressed as anti-FXa activity was detected in 180 (88%) samples. At univariate analysis, ACT, R-kaolin (R-k), and DR significantly correlated with plasma heparin concentration (respectively, p = 0.007, p = 0.006, and p = 0.002). At multivariate analysis, R-k and DR remained associated with plasma heparin concentration (respectively, p = 0.014 and p = 0.004). Greater quartiles of heparin were associated with higher values of R-k and DR. Combined procedures had significantly lower DR than isolated procedures (p = 0.017), and CPB time and heparinization time positively correlated with R-k (respectively, p = 0.044 and p = 0.022). No association was observed between heparin concentration, ACT, and TEG parameters with postoperative bleeding and need for blood and blood components transfusions. CONCLUSIONS: Heparin rebound and incomplete heparin reversal are very common phenomena after cardiac surgery with CPB; ACT is not able to detect residual heparin activity, whereas TEG analysis with and without heparinase allows the diagnosis of heparin rebound.

Isthmus endoprosthesis stent-graft treatment: implantation of relay dedicated device.

Among the 123 patients treated in our department by endovascular stent graft, 113 (91.8%) were identified as having involvement of the isthmus. Therefore, the incorrectly defined descending aortic disease is essentially a pathology of the isthmus that represents the distal portion of the arch. The key to the treatment of all types of aortic lesions rests on understanding the morphology of this region gifted with a "double S" configuration. Current thoracic devices are noncompliant systems and should be modified greatly, taking into account that the media of the aorta has a semi-compliant behavior. The resultant of power transmission is oriented at 45 degrees and produces a transmural radial force that animal implantation has demonstrated to be a torsional movement. The improvements in new devices actually result in a new generation of endoprostheses that seem to be closely related to the anatomy of the patient by increasing the conformability and, therefore, we expect an increase in durability. To test these features, we have studied a new stent graft in different settings of thoracic aortic disease. The new device should conform to current standards while simultaneously transmitting torsional forces. The dedicated delivery system should be arch-compatible, flexible but sufficiently rigid, and able to be three-dimensionally oriented. Moreover, the new stent graft should follow the three-dimensional anatomy of the "double S" configuration of the isthmus area and thus reduce the mismatch between the aorta and the device itself.

Midterm evaluation of the Sorin Bicarbon heart valve prosthesis: single-center experience.

BACKGROUND: The purpose of this study was to perform midterm evaluation of the clinical performance of the Sorin Bicarbon mechanical heart valve prosthesis. METHODS: From November 1992 to December 2002, 328 patients underwent isolated aortic (AVR; 156) or mitral (MVR; 172) valve replacement with the Sorin Bicarbon mechanical valve. Concomitant surgery was performed in 83 patients (25.2%). RESULTS: Total hospital mortality was 5.2%. Survival at 7 years was 79.5% for AVR and 82.4% for MVR. Kaplan-Meier freedoms from valve-related complications were as follows: thromboembolism 92.7% (AVR 94.8%, MVR 92.1%); bleeding 93% (AVR 91.9%, MVR 94.5%); nonstructural dysfunction 96.6% (AVR 94.7%; MVR 97.9%); endocarditis 97.7% (AVR 97.4%, MVR 98.1%); and reoperation 95.7% (AVR 96.6%, MVR 93.9%). Overall freedom from valve-related death was 93.2% (AVR 99.3%, MVR 91.2%). At the end of follow-up, 88.9% of survivors were in New York Heart Association class I or II. CONCLUSIONS: The Sorin Bicarbon valve is a satisfactory mechanical valve prosthesis with low mortality and morbidity and good functional results.

Stent graft treatment of thoracic aortic disease.

This study was a retrospective analysis of both the efficacy and long-term outcome of endovascular management of thoracic aortic disease. From March 1999 to August 2003, 129 patients (110 males; 19 females) were enrolled. They were divided into four groups: aneurysms (41, 5 of which acutely ruptured, Group A), post-traumatic lesions (24, 14 acute and 10 chronic, Group B) and complicated type B dissections (42, 23 acute and 19 chronic, Group C). Twenty-two of the 129 patients with chronic type B dissection, not suitable for endovascular treatment, received medical management only (Group D). All patients underwent computed tomography (CT) scan and angiography as preoperative assessment. Stent-graft systems were Talent -Medtronic, Excluder-Gore, Zenith-Cook and Endofit-Endomed, deployed by transesophageal echocardiography (TEE) monitoring. An optimal deployment with sealing of the graft was achieved in 95.3% (102/107) of the treated patients discharged in good condition within 6 days. Five patients (3 in Group A and 2 in Group C) underwent endovascular completion of the elephant trunk technique successfully. In 5 patients affected by atherosclerotic aneurysm, in a single-time procedure, we have also treated the abdominal aortic aneurysm by endovascular. No spinal cord injuries were observed. The follow up (average: 20.82+/-10.01 months), performed with serial chest CT scans, was 100% complete. No stent-graft related complications were detected. In 2 patients with chronic dissection, an asymptomatic type II endoleak was detected. A total of 4 hospital deaths resulted in an overall operative mortality rate of 3.7%. Seven patients (6.5%) died during the follow-up period, whereas a 31.8% (7/22) mortality rate (p<0.001) was observed within the medical treatment group. Endovascular treatment of thoracic aortic diseases, even in the acute phase, may represent a valid option, especially when compared to medical therapy.

[Anticoagulation in patients with cardiac valve prostheses]. / Trattamento anticoagulante nei portatori di protesi valvolari cardiache.

Patients with heart valve prostheses carry a higher risk of thromboembolic events compared to the normal population. In many cases anticoagulation is required after heart valve replacement. Thromboembolic risk is related to valve prosthesis design, patient own characteristics and adequacy of anticoagulation. Recent advance in the understanding of the pathophysiology of thrombus formation and pharmacological characteristics of most used anticoagulants are discussed. Suggestions for anticoagulation regimen are given according to recent randomised clinical trials based on prosthesis type, site of implant and patients clinical characteristics. Emphasis is given for cumbersome situations such as pregnancy and major hemorrhage in which anticoagulation has to be interrupted.

Risk stratification for in-hospital mortality after cardiac surgery: external validation of EuroSCORE II in a prospective regional registry.

OBJECTIVES: To evaluate performance of the European System for Cardiac Operation Risk Evaluation (EuroSCORE II), to assess the influence of model updating and to derive a hierarchical tree for modelling the relationship between EuroSCORE II risk factors and hospital mortality after cardiac surgery in a large prospective contemporary cohort of consecutive adult patients. METHODS: Data on consecutive patients, who underwent on-pump cardiac surgery or off-pump coronary artery bypass graft intervention, were retrieved from Puglia Adult Cardiac Surgery Registry. Discrimination, calibration, re-estimation of EuroSCORE II coefficients and hierarchical tree analysis of risk factors were assessed. RESULTS: Out 6293 procedures, 6191 (98.4%) had complete data for EuroSCORE II assessment with a hospital mortality rate of 4.85% and EuroSCORE II of 4.40 ± 7.04%. The area under the receiver operator characteristic curve (0.830) showed good discriminative ability of EuroSCORE II in distinguishing patients who died and those who survived. Calibration of EuroSCORE II was preserved with lower predicted than observed risk in the highest EuroSCORE II deciles. At logistic regression analysis, the complete revision of the model had most of re-estimated regression coefficients not statistically different from those in the original EuroSCORE II model. When missing values were replaced with the mean EuroSCORE II value according to urgency and weight of intervention, the risk score confirmed discrimination and calibration obtained over the entire sample. A recursive tree-building algorithm of EuroSCORE II variables identified three large groups (55.1, 17.1 and 18.1% of procedures) with low-to-moderate risk (observed mortality of 1.5, 3.2 and 6.4%) and two groups (3.8 and 5.9% of procedures) at high risk (mortality of 14.6 and 32.2%). Patients with low-to-moderate risk had good agreement between observed events and predicted frequencies by EuroSCORE II, whereas those at greater risk showed an underestimation of expected mortality. CONCLUSIONS: This study demonstrates that EuroSCORE II is a good predictor of hospital mortality after cardiac surgery in an external validation cohort of contemporary patients from a multicentre prospective regional registry. The EuroSCORE II predicts hospital mortality with a slight underestimation in high-risk patients that should be further and better evaluated. The EuroSCORE II variables as a risk tree provides clinicians and surgeons a practical bedside tool for mortality risk stratification of patients at low, intermediate and high risk for hospital mortality after cardiac surgery.

Haemostasis alterations in coronary artery bypass grafting: comparison between the off-pump technique and a closed coated cardiopulmonary bypass system.

OBJECTIVES: To compare coagulation and fibrinolysis activation in off-pump coronary artery bypass operation and in patients in whom a closed phosphorylcholine-coated cardiopulmonary bypass system was applied. Cardiopulmonary bypass induces activation of coagulative and fibrinolytic systems, which together with intraoperative haemodilution augment the risk of postoperative bleeding and transfusion of blood products. METHODS: Thirty-six off-pump coronary artery bypass and 36 coronary artery bypass grafting patients in whom a closed, phosphorylcholine-coated cardiopulmonary bypass system with a closed-collapsible venous reservoir (Physio group) was used were prospectively enrolled. Activation of coagulation and fibrinolytic systems was assessed evaluating the release of prothrombin fragment 1.2 and plasmin-antiplasmin complex preoperatively (T0), 30 min after heparin administration (T1), 15 min after protamine administration (T2), 3 h after protamin administration (T3) and on postoperative days 1 (T4) and 5 (T5). Platelet function was evaluated through Platelet Function Analyzer 100(®). RESULTS: During the operation, prothrombin fragment 1.2 and plasmin-antiplasmin levels were slightly higher in the Physio group, the difference being not statistically significant. In the off-pump coronary artery bypass group, prothrombin fragment 1.2 was significantly higher at T3 (618.7 ± 282.7 vs 416.6 ± 250.2 pmol/l; P = 0.006), T4 (416.7 ± 278.8 vs 310.2 ± 394.6 pmol/l; P < 0.001) and T5 (629.3 ± 295.2 vs 408.4 ± 409.7 pmol/l; P = 0.002), and plasmin-antiplasmin was significantly higher at T4 (731.1 ± 790 vs 334 ± 300.8 ng/ml; P = 0.019) and T5 (1744.4 ± 820.7 vs 860.1 ± 488.4 ng/ml; P = 0.003). Platelet Function Analyzer 100® closure time values were significantly higher in the Physio group patients at T3 (131.3 ± 105.7 vs 215.6 ± 58.9 s; P = 0.002). The off-pump coronary artery bypass patients had greater chest tube drainage (874.3 ± 371.5 vs 629.1 ± 334.5 ml; P = 0.005). The mean priming volume was 1240 ± 215 ml in the Physio group. Much more Physio patients received red blood cell transfusions (14 vs 25 patient; P = 0.009), because of higher intraoperative transfusion rates (6 vs 15 patients; P = 0.016). Despite similar preoperative haemoglobin levels (13 ± 1.2 vs 12.6 ± 1.4 g/dl; P = 0.2), postoperative haemoglobin levels were significantly lower in the Physio group. CONCLUSIONS: The Physio cardiopulmonary bypass approach does not significantly alter haemostasis during the operation compared with off-pump coronary artery bypass providing a reduced activation in the postoperative period reducing also chest tube drainage. However, further priming volume reduction is required to decrease intraoperative red blood cell transfusion.

Formation of anti-platelet factor 4/heparin antibodies after cardiac surgery: influence of perioperative platelet activation, the inflammatory response, and histocompatibility leukocyte antigen status.

BACKGROUND: Anticoagulation therapy with heparin induces antibodies that recognize multimolecular complexes of platelet factor 4 bound to heparin (anti-platelet factor 4/heparin antibodies). Considering that cardiac surgery induces an intense platelet activation and proinflammatory response, we examined the relationship between formation of anti-platelet factor 4/heparin antibodies and plasma levels of platelet factor 4 and interleukin 6. We also examined the relationship between anti-platelet factor 4/heparin seroconversion and the histocompatibility leukocyte antigen system. METHODS: In 71 patients undergoing cardiac surgery, anti-platelet factor 4/heparin antibody levels were evaluated by means of enzyme-linked immunosorbent assay preoperatively and 14 days postoperatively. Platelet serotonin release assays were performed to assess the platelet-activating potential of the antibodies. Plasma levels of platelet factor 4 and interleukin 6 were assayed at prespecified time points. Histocompatibility leukocyte antigen status was assessed preoperatively in all patients and was compared with that of 6156 healthy subjects. RESULTS: Thirty-seven (52%) patients had anti-platelet factor 4/heparin antibodies with an OD value of 0.45 or greater in 1 or more of the assays. Applying strict seroconversion criteria (>2-fold increase in Optical Density), only 16 (22.5%) patients had evidence of anti-platelet factor 4/heparin antibody seroconversion after the operation. Neither the presence of anti-platelet factor 4/heparin antibodies nor seroconversion influenced postoperative outcomes. The CW4 allele was significantly more frequent among seroconverted patients (46.9% vs 19.1%, P = .002). Platelet factor 4 levels did not influence seroconversion. Patients with anti-platelet factor 4/heparin levels of 0.45 OD units or greater 14 days after the operation had significantly higher interleukin 6 levels measured 1 hour after protamine administration. DISCUSSION: Patients with a greater amount of perioperative inflammation could be more likely to have anti-platelet factor 4/heparin antibodies 1 to 2 weeks later. We provide additional evidence that the histocompatibility leukocyte antigen CW4 confers genetic susceptibility in an acquired inflammatory disorder that includes the anti-platelet factor 4/heparin immune response.

Superior mesenteric artery blood flow modifications during off-pump coronary surgery.

BACKGROUND: Patients undergoing cardiac surgery are at increased risk of gut hypoperfusion. During off-pump surgery, hemodynamic derangements at the time of heart displacement could reduce splanchnic perfusion, outweighing the beneficial effects of avoiding cardiopulmonary bypass. The purpose of this study is to assess, prospectively, blood flow modifications in the superior mesenteric artery during off-pump surgery using transesophageal echocardiography. METHODS: In 19 patients undergoing multivessel elective off-pump coronary revascularization, systemic hemodynamics and superior mesenteric flow were assessed. Blood flow in the superior mesenteric artery was evaluated with duplex ultrasound using a transesophageal echo probe. Measurements were made four times: T0 (baseline), T1 (left anterior descendent anastomosis), T2 (heart displacement to expose the inferolateral and inferior walls), and T3 (closed chest, at the end of surgery). RESULTS: Superior mesenteric blood flow significantly decreased at T2 (from 426.4 +/- 83.1 mL to 212.9 +/- 48.6 mL, p < 0.001), when also cardiac output was reduced. The percentage of the cardiac output directed toward the mesenteric arterial bed was also decreased at this time. At the end of surgery (T3), whereas cardiac output returned to the initial values, mesenteric flow was significantly increased compared with baseline, with a higher percentage of the systemic output flowing through the superior mesenteric artery. CONCLUSIONS: Hemodynamic changes during off-pump coronary surgery induce a significant mesenteric hypoperfusion followed by a hyperemic response at the end of surgery. Transesophageal echo-Doppler allows the intraoperative measurement of blood flow distribution to splanchnic viscera.

Cardiac troponin I release after coronary artery bypass grafting operation: effects on operative and midterm survival.

BACKGROUND: Markers of myocardial necrosis are usually elevated in patients who have undergone a coronary bypass operation with cardiac arrest. The preferred marker in detecting acute myocardial ischemia is cardiac troponin I (cTnI). However, its ability to predict short-term and, particularly, midterm outcome after coronary bypass operations is uncertain. METHODS: Two hundred thirty unselected patients undergoing surgical revascularization had cTnI measured preoperatively and 11 times postoperatively. Receiver operating characteristic curves were constructed using cTnI postoperative peak values in order to assess the prognostic sensitivity and specificity of the test. The cut-off value of 13 ng/mL was used to assess the prognostic significance of the peak cTnI postoperative release for short-term and midterm outcomes. RESULTS: One hundred forty-six patients (63.5%) had postoperative cTnI peak values less than 13 ng/mL (mean peak value, 6.6 +/- 3.1 ng/mL) and 84 patients (36.5%) had postoperative cTnI peak values greater than 13 ng/mL (mean peak value, 45.5 +/- 59.9 ng/mL). Patients with peak cTnI greater than 13 ng/mL were older and had higher preoperative cTnI values. They required both longer cross-clamp time and CPB time. Moreover, hospital death in the cTnI greater than 13 ng/mL group (9.5% versus 0.7%, p = 0.0009) was significantly higher. Multivariate analysis showed that cTnI greater than 13 ng/mL was the only independent predictor of hospital death (odds ratio 10.33, p = 0.04) and hospital death from cardiac causes. A 2-year follow-up demonstrates that cTnI postoperative release had no influence on midterm mortality and hospitalization for due to cardiac illness. CONCLUSIONS: Cardiac troponin I is a valuable marker for immediate myocardial damage after coronary bypass operations. Its postoperative release does not predict midterm outcome.