Andreas Boening

Long-term results after surgical correction of atrioventricular septal defects

OBJECTIVE Review of the results of surgical correction of atrioventricular septal defects (AVSD), identification of risk factors for mortality and failure of left AV valve repair and determination of the impact of cleft closure on postoperative AV valve function. METHODS Between 1975 and 1995, 121 consecutive patients (55 males, 66 females) underwent surgery for biventricular correction of AVSD with a median age of 1.2 years and a median weight of 7.6 kg. Sixty-five patients had a complete AVSD, 17 patients an intermediate type, and 39 patients a partial AVSD. The left AV valve (MV) cleft was closed in 53 patients (43.8%). The mean follow-up time is 7.2+/-4.6 years. RESULTS Actuarial survival of the whole group after 1 year was 80%, after 10 and 20 years 78 and 65%, respectively. There were 18 early deaths (7-day mortality, 10.7%; 30-day mortality, 14.9%) and eight late deaths. In a univariate analysis, risk factors for early or late death were diagnosis of complete AVSD (P=0.006), no cleft closure (P=0.024), postoperative complications (P<0.0001), age <1.2 years (P=0.017), weight <7.6 kg (P=0.002), PA/Ao pressure ratio >0.7 (P<0.0001), and ECC time >110 min (P=0.002). In the multivariate analysis, postoperative complications (P=0.003) and PA/Ao pressure ratio >0.7 (P=0.001) had parallel effects on the postoperative risk for mortality. Moderate or severe MV regurgitation was present in six patients (6.0%) in the first evaluation after discharge and in 20 patients (20.4%) in the most recent postoperative control. There were 25 reoperations in 17 patients, of which 15 had to be performed for MV regurgitation and two for MV stenosis. Freedom from reoperation was 91% at 1 year, 79% at 10 years, and 76% at 15 and 20 years. We could not identify a statistically significant risk factor for reoperation. CONCLUSIONS In patients with AVSD of various morphologies closure of the left AV valve cleft significantly improves outcome without affecting the need for reoperation. Risk factors for early and late death (multivariate analysis) were a pulmonary/aortic pressure ratio >0.7 and the occurrence of any complication after surgery. The concept of an early surgical AVSD correction before an increase in pulmonary vascular resistance and AV valve deformations occur would represent a better surgical option than a late correction as done in our series. Early correction allows for reduction of early mortality, superior long-term survival rates and a high freedom from subsequent valve degeneration.

Aortic valve replacement in octogenarians: identification of high-risk patients §

OBJECTIVE This study identifies high-risk octogenarians for surgical aortic valve replacement (AVR) because with the current advances in transcatheter valve therapy, a definition of patient selection criteria is essential. METHODS Between 1996 and 2006, 493 consecutive octogenarians with symptomatic aortic stenosis underwent AVR with and without (51%) concomitant coronary artery bypass grafting (CABG). To identify high-risk patient groups, risk factors of 6-month mortality were determined using multivariable logistic regression. RESULTS The 30-day mortality rate was 8.4% and it increased up to 15.2% until 6 months after AVR. Independent risk factors of 6-month mortality were patients older than 84 years (odds ratio (OR): 2.2 (1.29-3.61)), left ventricular ejection fraction <60% (OR: 2.5 (1.35-4.61)), body mass index (BMI) <24 (OR: 2.0 (1.22-3.36)), creatinine (OR: 1.6 (1.04-2.53)) and blood glucose (OR: 1.01 (1.001-1.009)). High-risk groups were patients older than 84 years with an ejection fraction <60% (6-month mortality 28%) and patients younger than 84 years with an ejection fraction <60% and a BMI <24 (6-month mortality 23.2%). These high-risk groups comprised 37% of the patient population. After isolated AVR, the 30-day mortality and survival at 1 and 5 years was 11.6%, 69% and 35% in this high-risk group, respectively. In octogenarians with an STS score >10 and an EuroScore >20, the 30-day mortality and survival at 1 year was 10.5% and 80%, 11.6% and 77%, respectively. CONCLUSIONS In most octogenarians, AVR is a safe and beneficial procedure. In high-risk octogenarians, identified by STS score >10, EuroScore >20 and by simple three risk factors (age >84 years, ejection fraction <60% and BMI <24), the mortality after surgical AVR was no different from the currently reported outcome after transcatheter AVI.

Anemia Before Coronary Artery Bypass Surgery as Additional Risk Factor Increases the Perioperative Risk

BACKGROUND A negative relationship between anemia before coronary artery bypass graft (CABG) surgery and the perioperative mortality has been shown. We tried to clarify whether anemia only expresses an increased perioperative risk or is a risk factor per se in a two-institution database. METHODS In the years 2005 and 2006, 185 of 3,311 patients undergoing isolated first-time CABG surgery had anemia defined as hematocrit less than 33% or Hb≤11 g/dL. Preoperative and postoperative data of patients having anemia and patients having normal hematocrit were compared using χ2-tests or Fishers exact tests regarding structural group differences. To determine factors influencing perioperative mortality, methods of logistic regression were used. RESULTS The 30-day mortality of anemic patients (12.9%) was significantly higher (p<0.001) than the mortality of nonanemic patients (2.2%). Patients having anemia, though, had a worse risk profile before surgery: high European System for Cardiac Operative Risk Evaluation values (median, 7 in anemic patients versus 4 in nonanemic patients), acute myocardial infarction (9.7% in anemic versus 2% in nonanemic patients), diabetes mellitus (45.4% in anemic versus 33.3% in nonanemic patients), and cardiogenic shock (5.4% in anemic versus 0.8% in nonanemic patients) were significantly more frequent in the anemic group. However, taking these risks in account, the logistic regression revealed preoperative anemia still to be a mortality-increasing factor in patients undergoing CABG surgery (odds ratio 3.727, confidence interval: 2.196 to 6.324). Furthermore, anemia was a risk factor for perioperative morbidity (major adverse cardiovascular events) after CABG surgery (odds ratio 2.199, confidence interval: 1.423 to 3.397). CONCLUSIONS In our patient group undergoing CABG surgery, preoperative anemia increased the mortality risk by 3.4, even when taking the higher perioperative risk of anemic patients into consideration.

Early and medium-term results after on-pump and off-pump coronary artery surgery: a propensity score analysis

BACKGROUND Comparative publications on beating-heart off-pump coronary artery bypass grafting (OPCAB) surgery versus conventional coronary artery bypass grafting (CCAB) surgery frequently do not offer conclusive information because of investigator bias. METHODS Trying to eliminate this problem, a propensity score analysis of the data of all CCAB patients (n = 517) and OPCAB patients (n = 133) operated on by the same surgeons during the same time period (1998 to 2001) was applied. After matching patients with similar propensity score values, 97 CCAB patients and 72 OPCAB patients entered the final analysis. RESULTS Early results were similar in both groups: the 30-day mortality reached 1.4% in the CCAB group and 2.8% in the OPCAB group; strokes did not happen. Perioperative myocardial infarctions occurred in 4.1% of the CCAB patients and 4.3% of the OPCAB patients. Drainage blood loss in the first 24 hours after surgery (830 +/- 687 mL, CCAB group; and 909 +/- 678 mL, OPCAB group) was similar (p = 0.06) in both groups. Medium term results (freedom from percutaneous transluminal coronary angioplasty or reoperation, freedom from myocardial infarction, freedom from stroke, and the quality of life) also were not significantly different between the off-pump and on-pump groups after a mean follow-up of 27 +/- 11 months. CONCLUSIONS Our results suggest that elective-surgery patients with coronary artery disease can be operated on either on-pump or off-pump with the same early and late mortality and morbidity.

Pulse pressure variation and stroke volume variation during different loading conditions in a paediatric animal model

Background: Previous studies in adult patients and animal models have demonstrated that pulse pressure variation (PPV) and stroke volume variation (SVV) can be used to predict the response to fluid administration. Currently, little information is available on the performance of these variables in infants and neonates. The aim of our study was to assess whether PPV and SVV can predict fluid responsiveness in an animal model and to investigate the influence of different tidal volumes applied.

Preoperative intra-aortic counterpulsation in high-risk patients undergoing cardiac surgery: a meta-analysis of randomized controlled trials

In contrast to the results of previous studies, recent randomized controlled trials (RCTs) failed to show a benefit of prophylactic aortic counterpulsation in high-risk patients undergoing cardiac surgery. The present analysis aims to redefine the effects of this treatment modality in the light of this new evidence. MEDLINE, EMBASE, CENTRAL/CCTR, Google Scholar and reference lists of relevant articles were searched for full-text articles of RCTs in English or German. Assessments for eligibility, relevance, study validity and data extraction were performed by two reviewers independently using prespecified criteria. The primary outcome was hospital mortality. A total of nine eligible RCTs with 1171 patients were identified: 577 patients were treated preoperatively with intra-aortic balloon pump (IABP) and 594 patients served as controls. The pooled odds ratio (OR) for hospital mortality (22 hospital deaths in the intervention arm, 54 in the control group) was 0.381 (95% CI 0.230-0.629; P < 0.001). The pooled analyses of five RCTs including only patients undergoing isolated on-pump coronary artery bypass grafting (n[IABP] = 348, n[control] = 347) also showed a statistically significant improvement in mortality for preoperative IABP implantation (fixed-effects model: OR 0.267, 95% CI 0.129-0.552, P < 0.001). The pooled OR for hospital mortality from two randomized off-pump trials was 0.556 (fixed-effects model, 95% CI 0.207-1.493, P = 0.226). Preoperative aortic counterpulsation was associated with a significant reduction in low cardiac output syndrome (LCOS) in the total population (fixed-effects model: OR 0.330, 95% CI 0.214-0.508, P < 0.001) as well as in the subgroup of CAGB patients (fixed-effects model: OR 0.113, 95% CI 0.056-0.226, P < 0.001), whereas there was no benefit in the off-pump population (fixed-effects model: OR 0.555, 95% CI 0.209-1.474, P = 0.238). Preoperative IABP implantation was associated with a reduction of intensive care unit (ICU) stay in all investigated populations with a greater effect in the total population [fixed-effects model: standard mean difference (SMD) -0.931 ± 0.198, P < 0.001] as well as in the subgroup of CAGB patients (fixed-effects model: SMD -1.240 ± 0.156, P < 0.001), compared with the off-pump group (fixed-effects model: SMD -0.723 ± 0.128, P < 0.001). Despite contradictory results from recent trials, the present study confirms the findings of previous meta-analyses that prophylactic aortic counterpulsation reduces hospital mortality, incidence of LCOS and ICU requirement in high-risk patients undergoing on-pump cardiac surgery. However, owing to small sample sizes and the lack of a clear-cut definition of high-risk patients, an adequately powered, prospective RCT is necessary to find a definite answer to the question, if certain groups of patients undergoing cardiac surgery benefit from a prophylactic IABP insertion.

Global End-Diastolic Volume During Different Loading Conditions in a Pediatric Animal Model

BACKGROUND:Estimating volume status in infants and neonates is challenging. Global end-diastolic volume (GEDV) and dynamic variables of preload, such as pulse pressure variation (PPV), may be alternative variables for estimating cardiac preload and fluid responsiveness. Therefore, we designed the present study to evaluate whether GEDV and PPV are suitable variables of preload and fluid responsiveness during rapidly changing loading conditions in a pediatric animal model. METHODS:Nineteen anesthetized and mechanically ventilated piglets (6.5 ± 0.8 kg) were studied during different loading conditions. Hemodynamic measurements, including central venous pressure, pulmonary capillary wedge pressure, PPV, GEDV, and cardiac output derived by transpulmonary thermodilution, cardiac output, and stroke volume index obtained by pulmonary artery thermodilution were performed at normovolemia, and after fluid administration, with 25 mL/kg of hydroxylethyl starch 6%. RESULTS:There was a significant percentage change of GEDV after volume loading (25% ± 17%) that resulted in significant changes of all hemodynamic variables except of heart rate and systemic vascular resistance index. GEDV was the only preload variable that significantly correlated with volume-induced percentage change in stroke volume index (r = −0.61, P = 0.005). Area under the receiver operating characteristic curve was 0.8 for GEDV (P < 0.02) and 0.6 for PPV (P = ns). CONCLUSIONS:In this pediatric animal model, GEDV derived from transpulmonary thermodilution was a reliable indicator of cardiac preload. Moreover, GEDV but not PPV, central venous pressure and pulmonary capillary wedge pressure accurately reflected fluid responsiveness.

From basic mechanisms to clinical applications in heart protection, new players in cardiovascular diseases and cardiac theranostics: meeting report from the third international symposium on "New frontiers in cardiovascular research"

In this meeting report, particularly addressing the topic of protection of the cardiovascular system from ischemia/reperfusion injury, highlights are presented that relate to conditioning strategies of the heart with respect to molecular mechanisms and outcome in patients’ cohorts, the influence of co-morbidities and medications, as well as the contribution of innate immune reactions in cardioprotection. Moreover, developmental or systems biology approaches bear great potential in systematically uncovering unexpected components involved in ischemia–reperfusion injury or heart regeneration. Based on the characterization of particular platelet integrins, mitochondrial redox-linked proteins, or lipid-diol compounds in cardiovascular diseases, their targeting by newly developed theranostics and technologies opens new avenues for diagnosis and therapy of myocardial infarction to improve the patients’ outcome.

Age and obesity-associated changes in the expression and activation of components of the AMPK signaling pathway in human right atrial tissue

BACKGROUND Obesity is associated with an increased incidence of left ventricular hypertrophy, diastolic dysfunction, heart failure, and premature cardiac aging. In the heart, intrinsic activation of the AMP-dependent protein kinase (AMPK) plays a pivotal role in the stress response to ischemia and hypertrophy. Furthermore, AMPK is an important regulator of cardiac mitochondrial biogenesis. The purpose of the present study was to investigate the influence of obesity and aging on the AMPK signaling pathway in human cardiac tissue. METHODS 60 male cardiac surgery patients were included in the study and divided into 4 groups (old normal weight: ON; old obese: OO; young normal weight: YN, young obese: YO) according to their body mass index (18.5-25: normal weight or 30-35: obese) and age (<55 years: young or >70: old) with 15 patients each. Right atrial tissue (RA) was analyzed for the expression of the AMPK upstream kinases CAMKK and LKB1, activation of AMPK as well as phosphorylation of the AMPK downstream targets ACC, eEF2, mTOR and eNOS. Epicardial adipose tissue was analyzed for the expression of the endogenous AMPK activator adiponectin. The metabolic state of all patients was further characterized in fasting blood samples. RESULTS Old patients (ON, OO) and young obese (YO) subjects displayed higher fasting glucose, insulin and leptin serum levels compared to the young, normal weight group, although HbA1c was below the threshold required for the diagnosis of type 2 diabetes. Serum adiponectin as well as total adiponectin protein expression in epicardial adipose tissue was decreased in these three groups. Analyses of adiponectin isoforms by native gel electrophoresis revealed significant differences in the high molecular weight (HMW) isoforms between the groups. Despite the low total serum adiponectin and HMW adiponectin, AMPK activation was high in the RA of obese patients (YO, OO). Among the AMPK upstream kinases, LKB1 expression showed a strong positive correlation with AMPK activation. While the phosphorylation of the AMPK downstream targets mTOR, eEF-2 and ACC was not altered, phospho-eNOS was significantly lower in old patients (ON, OO). Despite strong AMPK activation, mitochondrial biogenesis and respiration were impaired in old (ON, OO) and young obese (YO) subjects. CONCLUSION These data indicate that obesity and aging result in significant changes although many direct parameters in the AMPK signaling pathway are not changed in the same direction. LKB1 may represent a stronger activator of the AMPK pathway than adiponectin or the CAMKKs in human right atrial tissue.

The Pericardium-Reinforced Technique of Amputation of the Left Atrial Appendage: Quick, Safe, and Simple

Ligation or amputation of the left atrial appendage is indicated in several surgical procedures but has been shown ineffective in many cases, depending on the method used. The only 100% effective means of excluding the left atrial appendage from the circulation is by complete resection. Complicating complete resection or amputation is the thin, fragile, delicate left atrial tissue, with a certain incidence of bleeding occurring. To handle this tissue adequately, we developed a safe and easy method for amputation of the left atrial appendage using autologous pericardium as reinforcement.