Andreas Böning

A Multicenter Trial of Remote Ischemic Preconditioning for Heart Surgery

BACKGROUND Remote ischemic preconditioning (RIPC) is reported to reduce biomarkers of ischemic and reperfusion injury in patients undergoing cardiac surgery, but uncertainty about clinical outcomes remains. METHODS We conducted a prospective, double-blind, multicenter, randomized, controlled trial involving adults who were scheduled for elective cardiac surgery requiring cardiopulmonary bypass under total anesthesia with intravenous propofol. The trial compared upper-limb RIPC with a sham intervention. The primary end point was a composite of death, myocardial infarction, stroke, or acute renal failure up to the time of hospital discharge. Secondary end points included the occurrence of any individual component of the primary end point by day 90. RESULTS A total of 1403 patients underwent randomization. The full analysis set comprised 1385 patients (692 in the RIPC group and 693 in the sham-RIPC group). There was no significant between-group difference in the rate of the composite primary end point (99 patients [14.3%] in the RIPC group and 101 [14.6%] in the sham-RIPC group, P=0.89) or of any of the individual components: death (9 patients [1.3%] and 4 [0.6%], respectively; P=0.21), myocardial infarction (47 [6.8%] and 63 [9.1%], P=0.12), stroke (14 [2.0%] and 15 [2.2%], P=0.79), and acute renal failure (42 [6.1%] and 35 [5.1%], P=0.45). The results were similar in the per-protocol analysis. No treatment effect was found in any subgroup analysis. No significant differences between the RIPC group and the sham-RIPC group were seen in the level of troponin release, the duration of mechanical ventilation, the length of stay in the intensive care unit or the hospital, new onset of atrial fibrillation, and the incidence of postoperative delirium. No RIPC-related adverse events were observed. CONCLUSIONS Upper-limb RIPC performed while patients were under propofol-induced anesthesia did not show a relevant benefit among patients undergoing elective cardiac surgery. (Funded by the German Research Foundation; RIPHeart ClinicalTrials.gov number, NCT01067703.).

Different approaches for minimally invasive closure of atrial septal defects

BACKGROUND To improve the acceptance of cosmetic results after closure of atrial septal defects, anterior or lateral thoracotomies are preferred rather than median sternotomies. Along with the availability of minimally invasive techniques, a further reduction in incision length appeared feasible while preserving thoracic stability. METHODS Various minimally invasive approaches differing in the type of incision and mode of cannulation have been applied under conditions of normothermic ventricular fibrillation. In technique 1 (n = 5), a right parasternal mini-incision was combined with a central aortic and bicaval cannulation. Technique 2 (n = 2) was composed of an anterior submammary mini-incision with femoral arterial and central bicaval cannulation. To optimize the surgical access, the transincisional cannulation of the superior vena cava was replaced by a percutaneous cervical cannulation (technique 3, n = 17). RESULTS Effective atrial septal defect closure assessed by intraoperative echocardiography was achieved in all patients. Central neurologic complications were completely absent. Besides temporary atrial fibrillation in one case, no other cardiac complications occurred. There were no cases with complicated wound healing. CONCLUSIONS Along with modified cannulation techniques and intraoperative echocardiography, minimally invasive techniques can be safely applied for atrial septal defect closure. Submammary incisions were highly accepted and allowed for adequate surgical exposure.

Minimally invasive coronary artery revascularization on the beating heart

BACKGROUND The quality of surgical beating heart revascularization is frequently questioned, especially when the surgical access is limited. Nevertheless, the number of off-pump coronary procedures is expanding worldwide. METHODS Since getting started with minimally invasive direct coronary artery bypass to anterior myocardial vessels in June 1996, 306 patients received left internal mammary artery grafting through an anterior minithoracotomy. Risk increasing comorbidities were present in 168 of them. Particular attention was paid to early postoperative angiographic results and complications. RESULTS The 30-day mortality summed up at 1.0% and was limited to patients with additional risks for conventional bypass grafting. Early postoperative control angiographies in 232 patients confirmed a global patency rate of 97.8%, revealing in addition four unexpected malinsertions to diagonal branches. In surviving patients major complications like myocardial infarction, stroke, or multiorgan failure were completely absent. CONCLUSIONS Minimally invasive direct coronary artery bypass grafting appears to allow for a safe and effective revascularization of the left anterior descending artery by use of the left internal mammary artery. Especially patients with risk increasing comorbidities should benefit from this approach, provided the surgical indication based on a dominating left anterior descending artery lesion. Angiographic minimally invasive direct coronary artery bypass results seem to fulfill the expectations generated by results obtained in conventional left internal mammary artery grafting and appear to be superior to interventional means.

Is there really a clinical benefit of using minimized extracorporeal circulation for coronary artery bypass grafting

BACKGROUND Minimized extracorporeal circulation is intended to reduce the negative effects associated with cardiopulmonary bypass. This prospective study was performed to evaluate whether minimized extracorporeal circulation has a clinical benefit for coronary artery surgery patients compared to standard extracorporeal circulation. METHODS Sixty patients were randomized into two study groups: 30 patients underwent coronary artery bypass grafting using minimized extracorporeal circulation and 30 patients were operated using standard extracorporeal circulation. Baseline characteristics, intraoperative details, postoperative data, perioperative blood chemistry determinations of hematocrit, platelets, muscle-brain fraction of the creatine kinase, cardiac troponin T and colloid osmotic pressure as measurements of intrathoracic blood volume index and extravascular lung water index were compared. RESULTS Baseline characteristics and intraoperative details of both groups were similar. Patients who underwent minimized extracorporeal circulation showed more short-term dependency on norepinephrine ( P < 0.01). Their maximal postoperative muscle-brain fraction of the creatine kinase was lower ( P < 0.05) and their hematocrit on arrival in the intensive care unit was higher ( P < 0.01). No other significant differences were found. In both collectives, values for hematocrit ( P < 0.001), platelets ( P < 0.001), colloid osmotic pressure ( P < 0.001) and intrathoracic blood volume index ( P < 0.05) decreased, while the extravascular lung water index did not change significantly during cardiopulmonary bypass. CONCLUSIONS A clinical advantage of minimized over standard extracorporeal circulation was not found. Furthermore, a higher number of patients in the minimized extracorporeal circulation group required postoperative norepinephrine infusions for hemodynamic stabilization. In summary, the presumed superiority of minimized extracorporeal circulation for coronary artery bypass grafting in standard patients could not be confirmed.

A prospective randomised multicentre clinical comparison of a minimised perfusion circuit versus conventional cardiopulmonary bypass.

OBJECTIVE Minimised perfusion circuits (MPCs) are expected to reduce the side effects of conventional cardiopulmonary bypass (CCPB); however, conclusive data from sufficiently powered clinical trials are lacking. The purpose of this study was to evaluate the safety and efficacy of the ROCsafeRX minimised perfusion circuit. METHODS A randomised, controlled, multicentre clinical trial comparing both perfusion circuits in patients subjected to elective coronary artery bypass and/or aortic valve replacement is described. The primary end points of safety, defined as procedure success without device-related complications, and secondary end point of efficacy, including reduction of transfusion requirement and incidence of atrial fibrillation, are analysed. RESULTS To date, 291 patients have been enrolled and randomised (146 MPC vs 145 CCPB). With the exception of a significantly higher male population in the MPC group (83.6% vs 71.0%, p=0.01), both groups were well matched for demographic data and type of surgery. There were no device-related complications but a hard-shell reservoir had to be integrated in one MPC because of a tear in the right atrium that was managed uneventfully. Total transfusion requirement (329+/-599 ml vs 783+/-1638 ml, p < or = 0.001) and erythrocyte transfusion (181+/-341 ml vs 434+/-798 ml, p < or = 0.001) were significantly reduced in the MPC group. The incidence of atrial fibrillation was significantly lower in the MPC group (7.1% vs 19.5%, p < or = 0.01), while freedom of major adverse events showed no significant difference. CONCLUSIONS Lack of device-related complications combined with a significant reduction in postoperative atrial fibrillation and transfusion requirements have shown the ROCsafeRX MPC to be both safe and efficient for large-scale use in cardiac patients. Additional data are expected to confirm these initial findings.

Are minimized perfusion circuits the better heart lung machines? Final results of a prospective randomized multicentre study.

Introduction: Minimized perfusion circuits (MPCs), although aiming at minimizing the adverse effects of cardiopulmonary bypass, have not yet gained popularity. This can be attributed to concerns regarding their safety, as well as lack of sufficient evidence of their benefit. Methods: Described is a randomized, multicentre study comparing the MPC - ROCsafeRX to standard cardiopulmonary bypass in patients undergoing elective coronary artery bypass grafting and/ or aortic valve replacement. Results: Five hundred patients were included in the study (252 randomized to the ROCsafeRX group and 248 to standard cardiopulmonary bypass). Both groups were well matched for demographic characteristics and type of surgery. No operative mortality and no device-related complications were encountered. Transfusion requirement (333 ± 603 vs. 587 ± 1010 ml; p=0.001), incidence of atrial fibrillation (16.3% vs. 24.2%; p=0.03) and the incidence of major adverse events (9.1% vs. 16.5%; p=0.02) were all in favour of the MPC group. Conclusion: These results confirm both the safety and efficacy of the ROCsafeRX MPC for a large variety of cardiac patients. Minimized perfusion circuits should, therefore, play a greater role in daily practice so that as many patients as possible can benefit from their advantages.

Coronary artery bypass surgery in diabetic patients.

Abstract  Background: Cardiovascular disease is a major cause of morbidity and mortality in patients with diabetes. This study examines the impact of diabetes on mortality and morbidity following coronary artery bypass surgery. Methods: We retrospectively analyzed 590 consecutive patients after coronary artery bypass grafting in 1998. Reoperations and combined procedures were excluded. A total of 137 diabetic (23.2%) and 453 nondiabetic patients were evaluated. Among the diabetics, 53 were treated with insulin and 84 were non‐insulin‐dependent. Diabetics suffered more frequently from hypertension, peripheral vascular disease, and more often had an increased body mass index (BMI). Results: There was no significant difference in mortality and major complications among insulin‐dependent diabetics, non‐insulin‐dependent diabetics, and nondiabetic patients. Diabetics suffered more often from superficial sternal wound infection and had a higher incidence of superficial wound infections at the vein harvest site. Conclusion: The present study suggests that diabetes increases the risk of superficial wound infections after coronary artery bypass grafting. But diabetics do not necessarily have an increased risk of major complications and mortality. (J Card Surg 2004;19:36‐40)

IABP before cardiac surgery: clinical benefit compared to intraoperative implantation

Background: The aim of this study was to determine whether preoperative compared to intraoperative intra-aortic balloon counterpulsation (IABP) is advantageous regarding 30-day and 2-year survival in high-risk patients (acute myocardial infarction, severely impaired left ventricular ejection fraction (LVEF), low output syndrome) undergoing coronary surgery. Methods: In the years 2004 to 2008, 156 consecutive patients undergoing coronary surgery with IABP support (119 preoperative, 37 intraoperative IABP) were observed. Applying Fisher’s exact test, as well as Wilcoxon and median tests, possible group differences were evaluated. After univariate analysis, models of logistic regression and Cox-regression were built. Results: Preoperative hemodynamic state and risk profile of the two patient groups were comparable: patients with preoperative IABP showed a similar level of urgency (21.9% vs. 18.9% emergencies), cardiogenic shock (8.4% vs. 10.8%), inotropes (8.4% vs. 8.1%), impaired LVEF (30.3% vs. 29.7%) and ventilation (5.9% vs. 5.4%) compared to patients with intraoperative IABP. Nevertheless, patients with intraoperative IABP demonstrated a significantly higher 30-day mortality rate (37.8% vs. 5.9%) and 2-year mortality rate (54.0% vs. 18.1%) compared to patients with preoperative IABP. Logistic regression revealed that patients with intraoperative IABP have a 16-times higher 30-day mortality rate after coronary surgery (OR: 16.386, 95% CI: 4.858-55.266) than patients with preoperative IABP. Two-year mortality (OR: 9.317, 95% CI: 3.430 to 25.311) and survival time were significantly better in patients with preoperative IABP therapy. Conclusion: Considering the significant benefit for patients with preoperative compared to intraoperative IABP and the absence of vascular problems after IABP insertion, the results of this study indicate a more liberal indication for IABP in high-risk patients before coronary bypass surgery.

Octogenarians Undergoing Combined Aortic Valve Replacement and Myocardial Revascularization: Perioperative Mortality and Medium-Term Survival

OBJECTIVE Aim of the study was to answer the question whether the mortality and morbidity of octogenarians undergoing combined aortic valve replacement and myocardial revascularization (AVR + CABG) is higher than that of younger patients. PATIENTS AND METHODS Between 01/1995 and 12/2002, 242 patients underwent AVR + CABG in our institution. 37 patients were older than 80 years (16 male, 21 female, median pressure gradient over the aortic valve: 53 mmHg, median EF: 62%), 205 patients were younger than 80 years (133 male, 72 female, median gradient 48 mmHg, median EF: 61%). NYHA class, aortic valve area and valve calcification were worse in the 80+ group. Biological valve prostheses were implanted in 94.6% of the older and in 45.4% of the younger patients (p < 0.001). RESULTS Perioperative complications occurred more often (p = 0.0188) in the 80+ group (86.5% experienced 1 or more complications) than in the 80- group (66.3%). Similarly, the MACE (Major Adverse Cardiovascular Events) rate was higher (p = 0.0448) in the 80+ group than in the 80- group. Bleeding occurred (p = 0.092) more often in younger (9.3%) than in older (0%) patients, while renal insufficiency was more frequent (p = 0.0164) in older (21.6%) than in younger patients (7.8 %). The 30-day mortality was higher (p = 0.0045) in older (21.6%) than in younger patients (5.8%). Multivariate analysis revealed an odds ratio for early death of 2.9 (CI 1.014-8.397) for patients older than 80 years. The late death rate within the first 5 years after surgery was comparable in both groups (80- group 24.4%, 80+ group 24.3%). Postoperative quality of life was significantly worse in the 80+ group in 4 out of 8 functions. CONCLUSIONS Octogenarians undergoing AVR + CABG have a relatively high perioperative complication rate and mortality, but show a stable medium-term survival. The perioperative complication rate is higher in older than in younger patients, and the postoperative quality of life with regard to bodily functions is acceptable but significantly worse than that of younger patients.

Long-term results of mechanical and biological heart valves in dialysis and non-dialysis patients.

INTRODUCTION We wanted to answer the question whether biological heart valves are inferior compared to mechanical heart valves in end-stage renal disease (ESRD) patients. METHODS Between 01/1996 und 12/2006, 44 of 3293 patients undergoing aortic valve replacement (AVR) in a single institution suffered from dialysis-dependent ESRD and underwent a follow-up investigation after 1.9 years (median). Twelve (28.9 %) of these patients received a biological, 32 (71.1 %) of these patients a mechanical aortic valve prosthesis. To evaluate a possible influence of the valve type (biological/mechanical) on survival, uni- and multivariate logistic regression was used. RESULTS ESRD patients after AVR had a relatively poor short-term (30-day mortality: 22.7 %) and long-term survival (median survival time: 24.7 months; 95 % CI: 0.2-47.7 months), irrespective of the type of heart valve prosthesis (hazard ratio for mortality depending on heart valve type in dialysis patients: 1.31, P = 0.400). Dialysis-dependent patients were not reoperated due to valve-related reasons. CONCLUSIONS The long-term survival of dialysis-dependent patients after AVR is low (5-year survival: 29.5 %) irrespective of the type of heart valve prosthesis. Therefore, the use of biological AVR is not contraindicated in this group of patients.