Postoperative arrhythmias after coronary artery and cardiac valvular surgery detected by long-term electrocardiographic monitoring.

Twenty-four hour long-term electrocardiographic recordings were used to supplement routine perioperative monitoring to determine the frequency and significance of arrhythmias occurring after coronary artery bypass graft surgery and cardiac valve replacement. Patients underwent “ambulatory” electrocardiographic monitoring for 24 hours before surgery and on the first and fifth days after discharge from intensive care.New arrhythmias occurred in 26 of 50 patients (52 per cent) after coronary artery bypass graft surgery and in six of 15 patients (40 per cent) after valve replacement. This high frequency of arrhythmia detection was directly attributable to the use of long-term electrocardiography. New atrial arrhythmias were common after both valvular and coronary artery bypass graft surgery (44 per cent and 38 per cent of patients, respectively). Ventricular arrhythmias were uncommon preoperatively in both groups but occurred frequently after coronary artery bypass graft surgery (36 per cent). Arrhythmias contributed to morbidity but not to mortality in this series.These results suggest that new atrial arrhythmias occurring after coronary artery bypass graft or valvular surgery may be related more to the immediate intrathoracic sequelae of surgery than to a specific underlying cardiac lesion, in contrast to ventricular arrhythmias which may be more specific for patients with ischemia. Long-term electrocardiographic recording is a useful technique to supplement routine methods of perioperative electrocardiographic monitoring.     

The impact of schistosomes and schistosomiasis on murine blood coagulation and fibrinolysis as determined by thromboelastography (TEG)

Schistosomes are parasitic platyhelminths that currently infect over 200 million people and cause the chronic debilitating disease schistosomiasis. While these large intravascular parasites can disturb blood flow, surprisingly they do not appear to provoke thrombus formation around them in vivo. In order to determine if the worms can alter their local environment to impede coagulation, we incubated adult worms (50 pairs) in murine blood (500 µl) for 1 h at 37 °C and, using thromboelastography (TEG), we compared the coagulation profile of the blood with control blood that never contained worms. Substantial differences were apparent between the two profiles. Blood that had been exposed to schistosomes clotted more slowly and yielded relatively poor, though stable, thrombi; all TEG measures of blood coagulation (R, K, α-angle, MA, G and TMA) differed significantly between conditions. No fibrinolysis (as determined by LY30 and LY60 values) was detected in either case. The observed TEG profile suggests that the worms are acting as local anti-coagulants. Blood recovered from schistosome-infected mice, however, does not behave in this way. At an early time point post infection (4-weeks), the TEG profile of infected murine blood is essentially the same as that of control blood. However at a later time point (7-weeks) infected murine blood clots significantly faster than control blood but these clots also break down faster. The R, K, α-angle, and TMA measures of coagulation are all significantly different between the control versus infected mice as are the LY30 and LY60 values. This profile is indicative of a hypercoagulable state with fibrinolysis and is akin to that seen in human patients with advanced schistosomiasis.     

Persistence of improved exercise tolerance and degree of revascularization after coronary bypass surgery. A prospective randomized study.

Exercise tolerance was repeatedly determined over a 2-year period in a series of 100 patients with coronary heart disease randomly allocated for medical therapy and coronary bypass surgery. The surgical group had a consistently better exercise tolerance than the medical group during the whole follow-up. Completeness of the revascularization, assessed by repeated graft and native vessel angiography, resulted in a marked improvement whereas incompletely revascularized patients exhibited only a marginal improvement which, nevertheless, to some degree exceeded the result of medical management alone. It is concluded that coronary bypass surgery and medical therapy, when indicated, result in markedly better exercise tolerance than medical management alone. This improvement persists up two years after the operation and is largely dependent on the completeness of the revascularization.     

Protamine dosage based on two titrations reduces blood loss after valve replacement surgery: a prospective, double-blinded, randomized study

Background

Postoperative hemorrhage following cardiopulmonary bypass in heart valve replacement patients may be caused by a mismatch of protamine and heparin. We hypothesized that a 2-titration-guided protamine dose would reduce protamine-heparin mismatch and bleeding in those patients.

Methods

Patients scheduled for elective cardiac valve replacement surgery (N = 60) were randomly divided into 3 groups. All patients received 2 titrations: the first at termination of cardiopulmonary bypass and the second at 5 minutes after the initial dose of protamine. In the control group, the initial protamine dose was based on the heparin dose received; the supplemental protamine dose was empirically determined. In the single-titration group, the initial dose was based on the first titration, while supplemental dose was empirically determined. In the 2-titration group, both initial and supplemental doses were based on titrations. Bleeding volumes were recorded from the time of first protamine dose to 24 hours after surgery.

Results

Most patients needed supplemental protamine according to second titrations. In the 2-titration group, 12 patients received supplemental protamine, whereas only 1 patient in the single-titration group and 6 in the control group received supplemental protamine (P = 0.003). The blood loss was significantly less in the 2-titration group (526 ± 131 mL) than in the control group (730 ± 385 mL; P = 0.019).

Conclusions

A higher dosage of protamine based on 2 titrations reduced blood loss after surgery, supporting the hypothesis that inadequate dosage of protamine contributes to hemorrhage after valve replacement surgery.     

The real impact of randomized clinical trials in heart valve surgery

PURPOSE OF REVIEW: The aim of this article is to evaluate the findings of clinical trials in cardiac valve surgery and to determine the real impact in standard of care. Also, publications on randomized clinical trials were reviewed as to integrity and validity. Nineteen randomized clinical trials were identified in 11 areas of operative and clinical management. RECENT DEVELOPMENTS: The Veterans Affairs and Edinburgh Heart Valve Trials confirmed the guidelines for indications for bioprostheses and mechanical prostheses. Even current prostheses have advanced technologies but the same valve-related complications determine indications. Randomized clinical trials of mechanical prostheses failed to determine prosthesis superiority. Bioprostheses of specific manufacturers contribute sub-optimal hemodynamics in small sizes. Two trials showed lack of superiority between aortic stented and stentless bioprostheses. Autografts, not allografts, are indicated for children because of structural valve deterioration of allografts. Atrial ablation surgery with concomitant mitral valve reconstruction/replacement is safe and efficacious with at least two energy sources. Minimally invasive aortic valve replacement does not provide superior results to conventional surgery. Patient-managed anticoagulation provides the most favourable thromboembolic and hemorrhagic rates with mechanical prostheses. Prosthesis sewing cuff impregnation with a bactericidal agent to reduce the incidence of prosthetic valve endocarditis was stopped because of increased incidence of major paravalvular leak requiring reoperation. SUMMARY: Randomized clinical trials, although limited in number, have provided advancement of the standard of care. Randomized clinical trials are indicated in the management of mild to moderate ischemic mitral regurgitation and evaluation of new transcatheter technologies to conventional surgery.     

Bivalirudin, blood loss, and graft patency in coronary artery bypass surgery

A safe and effective alternative is needed for patients in whom unfractionated heparin (UFH) or protamine is contraindicated (e.g., those with heparin-induced thrombocytopenia or allergy to protamine). Furthermore, choice of anticoagulant may influence graft patency in coronary surgery and may therefore be important even when there is no contraindication to UFH. Direct thrombin inhibitors have several potential advantages over UFH, demonstrated in acute coronary syndromes. However, there are also potential difficulties with their use related to lack of reversal agents and paucity of clinical experience in monitoring their anticoagulant activity at the levels required for cardiac surgery with cardiopulmonary bypass (CPB). In the first prospective randomized trial of an alternative to heparin in cardiac surgery, we compared bivalirudin (a short-acting direct thrombin inhibitor) with UFH in 100 patients undergoing off-pump coronary artery bypass (OPCAB) surgery. Blood loss for the 12 hours following study drug initiation in the bivalirudin group was not significantly greater than in the heparin group. Median graft flow was significantly higher in the bivalirudin group. We concluded that anticoagulation for OPCAB surgery with bivalirudin was feasible without a clinically important increase in perioperative blood loss. A larger study is needed to investigate the impact of improved graft patency on other clinical outcomes after cardiac surgery.     

The effect of fresh versus stored blood on post-operative bleeding after coronary bypass surgery: a prospective randomized study

In a prospective study, 237 patients undergoing a primary coronary bypass operation were randomized to receive 2 units of fresh whole blood (study group) or stored (2-5 d) blood (control group) at the end of the extracorporeal circulation. Serious post-operative bleeding necessitating a re-thoracotomy occurred in 4.2% of all patients with an equal distribution over the two groups. Post-operative haemoglobin content and platelet counts were higher in the study group, but the differences were small and clinically not important. There were no differences in transfusion requirements, post-operative blood losses and haemostatic parameters between the trial groups. At low post-operative platelet counts (below 120 X 10(9) platelets/l) however, patients in the control group lost significantly more blood and had increased transfusion requirements compared with patients in the study group (7.1 versus 4.8 units). These differences must be attributed to qualitative platelet defects in the transfused units of stored blood. The small, clinically insignificant, differences in two laboratory parameters between the study and control groups, and the increased transfusion requirements of a subpopulation of patients with low platelet counts in the control group do not justify giving fresh blood or prophylactic platelet transfusions to coronary bypass patients.     

Whole-gut irrigation versus enema in elective colorectal surgery: A prospective,randomized study

Whole-gut irrigation was compared with conventional mechanical bowel preparation in a prospective, randomized study. All 100 patients had a combination of ampicillin and metronidazole during and after colorectal surgery. Patients' complaints were equally frequent during the two preparations and were severe in 15 per cent. Gastric position of the tube for irrigation resulted in severe complaints in 3 of 26 patients and in the duodenal position, in severe complaints in five of 24. The time for irrigation was shorter than that for conventional preparation. Deep wound infections were equally frequent after irrigation (3/46) and conventional preparation (4/47). Seven patients were excluded, since no bowel resection had been performed. Collapse of the small and large intestine, as evaluated blindly during surgery, was more frequent after irrigation (P<0.05). Anastomotic leaks after left side resections were less frequent in patients with collapse of the small (P<0.001) and large (P<0.05) intestine. Five leakages among 29 patients after conventional preparation in contrast to one among 22 after whole-gut irrigation favor the latter, even if this difference did not reach statistical significance (0.05<P<0.10), since anastomotic leakage is lethal in a high number of patients.     

Effect of coronary arterial bypass surgery on exercise-induced ventricular arrhythmias. Long-term follow-up of a prospective randomized study.

The effect of coronary arterial bypass surgery on exercise-induced ventricular arrhythmias and their relation to sudden death was examined in 102 patients with stable angina pectoris randomly assigned to medical and surgical therapy (54 and 48 patients, respectively). Symptom-limited treadmill tests were performed at entry and at 1 and 5 years. The surgical group demonstrated significant improvement in exercise performance at 1 year compared with the medical group, and at 5 years exercise-induced ischemia as evidenced by S-T depression and exertional angina remained substantially decreased in the surgical group with little change in the medical group. However, the frequency and severity of exercise-induced ventricular arrhythmias in each group remained unchanged at 1 and 5 years from those at entry. Similar results were obtained from an evaluation of ventricular arrhythmias in the electrocardiogram at rest. With the exception of exercise-induced ventricular tachycardia and fibrillation, no relation was found between ventricular arrhythmias and sudden death. Coronary bypass grafting does not decrease the frequency or severity of exercise-induced or resting ventricular arrhythmias. In patients with stable angina pectoris, with the exception of ventricular tachycardia and fibrillation, exercise-induced ventricular arrhythmias are poor predictors of sudden death. The data suggest that exercise-induced ventricular arrhythmias may not be related to ischemia but to other effects of exercise such as cardiac stimulation by catecholamines or other factors.     

A prospective, randomized trial to assess the cost impact of pharmacist-initiated interventions.

BACKGROUND: Hospital pharmacists make many recommendations that improve patients' quality of care and/or reduce drug costs. While the impact of quality-of-care interventions is difficult to quantify, those limited to cost savings could be assessed in a prospective, randomized fashion. OBJECTIVE: To assess the impact of pharmacist-initiated interventions on cost savings. METHODS: Six pharmacists at a large university hospital recorded patient-specific recommendations for 30 days. All quality-of-care interventions were completed by the pharmacists, but those strictly aimed at reducing costs were stratified by drug class and randomized to an intervention or control group. Pharmacists contacted physicians with cost-saving recommendations in the intervention group, while control group patients were simply observed. MAIN OUTCOME MEASURE: Drug costs after randomization. RESULTS: Most (n=967 [79%]) of the 1226 interventions recorded were aimed at improving quality of care. The remaining 259 (21%) provided equivalent quality of care, but at less expense. These cost-saving interventions typically involved streamlining therapy to less expensive agents (39%), discontinuing an unnecessary medication (25%), or modifying the route of administration (24%). The group randomized to receive a pharmacist's intervention had drug costs that were 41% lower than those in the control group (mean, $73.75 vs $43.40; P<.001). Interventions involving anti-infective agents had the greatest cost savings (mean, $104.08 vs $58.45; P<.001). For our institution, this extrapolates to an annual savings of approximately $394,000 (95% confidence interval, $46,000-$742,000). As expected, these interventions had no impact on length of hospital stay, in-hospital mortality, 30-day readmissions, or the need to readminister the targeted medication or restart intravenous therapy. CONCLUSIONS: While interventions solely aimed at reducing costs represent a small portion of a pharmacist's activities, they can result in significant savings for an institution.     

A comparative study of the inhibitors of fibrinolysis in human, dog and rabbit blood.

Comparison of sera from dog, rabbit and man shows that dog serum contains most fibrinolytic inhibitor and human serum least. The inhibitors are potentiated by a variety of inorganic salts, of which sodium chloride is most effective. Euglobulin fractions precipitated from rabbit and human plasma at pH 5.3 contain small amounts of inhibitory material, whereas little remains in the corresponding dog euglobulin or in euglobulins from all three species when precipitated at pH 6.0. The potentiation of fibrinolytic inhibitors by sodium chloride differs between the three species, suggesting that their composition is not identical. Chloroform extraction removes a proportion of the inhibitory material from each serum.     

Measurement of postpartum blood loss using a new two-set liquid collection bag for vaginal delivery: A prospective,randomized, case control study

Background:Postpartum hemorrhage (PPH) is a major obstetric complication, and the real-time measurement of blood loss is important in the management and treatment of PPH. We designed a new two-set liquid collection bag (TSLCB) for measuring postpartum blood loss in vaginal delivery. The aim of this study was to evaluate the effectiveness of the TSLCB in separating the blood from the amniotic fluid during vaginal delivery and in determining the accuracy of the measured postpartum blood loss.Methods:A prospective, randomized, case control study was conducted in the Women''s Hospital, Zhejiang University School of Medicine, from March 2018 to April 2018. Sixty single pregnant women with spontaneous labor at 37–41 weeks without maternal complications were randomly divided into the experimental and control groups. The TSLCB was used to evaluate separately the amount of blood and amniotic fluid. For the control group, visual estimation and traditional plastic blood-collecting consumables were used to estimate the amount of postpartum blood loss. The measured blood loss between the two groups was compared, and the association of the measured blood loss with various clinical lab indices and vital signs was investigated.Results:The TSLCB (the experimental group) improved the detection of the measured blood loss compared with visual estimation and the traditional method (the control group) (P < .05). In the experimental group, correlation analysis showed that the measured blood loss at delivery and within 24 h of delivery was significantly associated with the decreased hemoglobin level, red blood cell count, and hematocrit level of patients (r = −0.574, −0.455, −0.437; r = 0.-595, −0.368, −0.374; P < .05). In the control group, only the measured blood loss within 24 h of delivery was associated with the decreased hemoglobin level (r = −0.395, P < .05). No blood transfusion and plasma expanders were required in the treatment of PPH for both groups.Conclusions:The TSLCB can be used to accurately measure the postpartum blood loss in vaginal delivery by medical personnel.     

Intraoperative cell salvage using swab wash and serial thromboelastography in elective abdominal aortic aneurysm surgery involving massive blood loss

The loss of 50% blood volume is one accepted definition of massive haemorrhage, which ordinarily would trigger the massive transfusion protocol, involving the administration of high ratios of fresh frozen plasma and platelets to allogeneic red cells. We investigated 53 patients who experienced >50% blood loss during open elective abdominal aortic aneurysm surgery to assess allogeneic blood component usage and coagulopathy. Specialist patient blood management practitioners used a tailored cell salvage technique including swab wash to maximise blood return. We assessed the proportion of patients who did not require allogeneic blood components and develop evidence of coagulopathy by thromboelastography (TEG) parameters. Blood loss was 50%–174% (mean [SD] 68% [27%]) of blood volume. The mean (SD) intraoperative decrease in haemoglobin concentration, assessed by arterial blood gas analysis, was 5 (13) g/l. No patient received allogeneic red cells intraoperatively. Four of the 53 (8%) patients received blood components in the first 24 h postoperatively at the anaesthetists’ discretion. No patient had intraoperative TEG changes indicative of fibrinolysis or coagulopathy. The 30-day mortality was 2% (one of 53). Reduction of allogeneic transfusion is one aim of patient blood management techniques. We have demonstrated virtual avoidance of allogeneic blood product transfusion despite massive blood loss. These data show possible alternatives to the current massive transfusion protocols to the management of elective vascular surgical patients.     

Impact of abciximab on coronary restenosis in diabetic patients undergoing elective paclitaxel-eluting stent implantation. A prospective, randomized, placebo-controlled study

AIMS: Recent studies suggested that abciximab reduces the risk of restenosis in diabetic patients receiving coronary bare metal stent. We sought to evaluate whether abciximab may reduce in-segment late luminal loss (LLL), in patients with diabetes mellitus undergoing elective drug-eluting stents (PES) implantation. METHODS and RESULTS: We conducted a prospective, randomized, double-blind study on diabetic patients after a paclitaxel-eluting stent (PES) implantation on de novo coronary artery lesions. 132 consecutive patients with diabetes (mean age 63.1+/-7.4 years, 82 males) were randomized to abciximab (n=66) or placebo (n=66). Among the 124 (93.9%) patients who underwent a 6-months angiographic follow-up, the mean difference in in-segment LLL between patients who received abciximab and placebo was 0.02 mm (P=0.8). In addition, the rates of angiographic in-segment restenosis were comparable between the two groups (14.3 versus 9.8%, P=0.5). Cumulative rates of clinical events did not differ (death: 1.5 versus 1.5, P=0.9 and MI: 1.5 versus 3%, P=0.8) between abciximab and placebo group, respectively. Similarly, the incidence of target lesion revascularization was 9.1% and 6.1% (P=0.7) at six months, in the two groups. CONCLUSIONS: Abciximab does not seem to have any impact on the extent of in-segment LLL in diabetic patients undergoing an elective PES implantation.     

The impact of pre-operative education on recovery following coronary artery bypass surgery. A randomized controlled clinical trial.

AIMS: Research has demonstrated the beneficial impact that pre-operative education exerts on the postoperative recovery of patients having surgery but little work has focused specifically on cardiac surgery. Therefore a randomized controlled trial was designed to elucidate the consequences of pre-operative education, given before admission, on postoperative pain, anxiety, depression and wellbeing in the 6 months following a first episode of coronary artery surgery. METHOD AND RESULTS: Three hundred and fifty-six people were randomized into the study, with 188 in the experimental and 168 in the control arms. Patients in the experimental group received the intervention, a day of education by members of the multidisciplinary team, prior to admission for surgery. Experimental and control subjects had the usual care, which involved education on admission and throughout their stay in hospital. Measurement was conducted on entry to the study, before randomization, and at 3 days, 6 weeks, 3 months and 6 months following operation. A variety of tools were used: the SF-36 Health Status questionnaire, the Hospital Anxiety and Depression scale, the General Well-Being questionnaire and a pain measurement tool. Analysis was done using the intention-totreat principle and non-parametric statistics. There were no significant differences between groups in the primary outcomes namely anxiety (P=0.09) and pain (P=0.48), or in depression (P=0.62) and wellbeing ('worn out' P=0.11; 'tense and uptight' P=0.29) 6 months after operation. This was also the case 3 days after coronary artery surgery. There was a significant difference in length of hospital stay (P=0.01) with the experimental group having the longer stay. These findings contrast with much of the existing evidence. CONCLUSION: The findings demonstrate that there is no benefit to be gained from this form of pre-operative education and that there is an associated increase in length of hospital stay. Future research could examine an ongoing programme of education and support, and might use alternative methods such as CD-ROM or the Internet.     

Influence of balloon size on initial success, acute complications, and restenosis after percutaneous transluminal coronary angioplasty. A prospective randomized study

Restenosis after percutaneous transluminal coronary angioplasty (PTCA) is strongly associated with incomplete initial dilatation. To determine if oversized PTCA balloons would reduce the restenosis rate without increasing the risk of arterial dissection and acute complications, we prospectively randomized 336 patients to receive either smaller or larger balloons. Thirty-four percent of patients had multivessel disease and 18% had multisite dilatation. One hundred sixty-nine patients were randomized to PTCA with a larger balloon and 167 to PTCA with a smaller balloon. Balloon:artery diameter ratios were 1.13 +/- 0.14 in the larger group and 0.93 +/- 0.12 in the smaller group (p less than 0.001). The trial was halted as clinically important differences in acute complications emerged. Emergency bypass graft surgery, usually for the treatment of arterial dissection, was required in 7.1% of patients in the larger balloon group and 3.6% of patients in the smaller balloon group (p = 0.15). Myocardial infarction (Q wave and non-Q wave) complicated 7.7% of procedures in which large balloons were assigned and 3.0% of procedures in which small balloons were assigned (p = 0.056). There were no deaths in either group. The incidence of bypass surgery was 1.7% when the balloon:artery ratio was less than 0.9, 3.1% when the ratio was 0.9-1.1, and 7.8% when it was greater than 1.1. Stepwise logistic regression analysis demonstrated that larger balloon assignment, multiple lesion dilatation, and multivessel coronary artery disease were independent predictors of emergency surgery. Angiographic restudy rates were 50% in the larger group and 60% in the smaller group (p = NS).(ABSTRACT TRUNCATED AT 250 WORDS)     

Felodipine-induced dilatation of epicardial coronary arteries. A randomized, double-blind study

Dilatation of large coronary arteries is of potential value in the treatment of angina pectoris. In this double-blind study, the acute effect of felodipine or placebo on coronary artery dilatation was studied in patients with severe angina pectoris with the aid of coronary arteriography. There were two parallel groups, one with 9 patients who received felodipine, the other with 12 patients who received placebo. Measurements of vessel diameters were performed at a proximal position of the affected artery, at the site of the stenosis, and distal to the lesion. The mean plasma felodipine concentration was 17+/-6 nmol/l. The systolic blood pressure was reduced from 156+/-15 to 145+/-13 mm Hg after felodipine (p less than 0.05), but was unaffected by placebo. The heart rate and arterial catecholamine levels were basically unchanged in both groups of patients. The proximal arterial segment was dilated 7% after felodipine (p = 0.05), the stenosis area 9% (N.S.) and the distal part of the vessel 7% (p less than 0.05). There were no changes in coronary diameters in the placebo group. In conclusion, felodipine dilates large coronary arteries, and this mode of action may be valuable in the treatment of patients with coronary artery disease, especially in cases where coronary spasm is a prominent feature.