Re-exploration Early after Cardiac Surgery in Adults: The Importance of Bleeding-Related Complications.

BACKGROUND: Re-explorations soon after cardiac surgery are mostly related to bleeding or unclear hemodynamic situations possibly related to heart compression resulting from pericardial hematoma. This condition has a significant impact on mortality, morbidity, and costs. The aim of this study was to analyze indications and outcomes of re-exploration for bleeding or pericardial tamponade early after cardiac surgery in adults. METHODS: The clinical data of 4790 consecutive adult patients who underwent cardiac surgery in our institution from January 2011 to May 2016 were retrospectively analyzed. RESULTS: We identified 331 re-explorations performed in 231 patients. Sixty-seven of these patients had >1 re- exploration. In most cases (88%), repeat sternotomy was performed. Most procedures (57%) were performed within the first 48 hours. In two-thirds of re-explorations, active bleeding or pericardial hematoma was verified. In the remaining cases, neither bleeding nor significant pericardial hematoma leading to tamponade was found. Among the cases with active bleeding causes, the most bleeding sites were found to be at the coronary anastomosis and the epicardial exposure harvesting site, as well as from the side branches of bypass grafts and intercostal arteries. CONCLUSIONS: The incidence of re-exploration after cardiac surgery in adults was low (4.8%). In about two-thirds of the cases, active bleeding or significant pericardial hematoma was found. The most common bleeding causes were the easiest to treat.

First experience with the Synergy Micro-Pump in patients in INTERMACS class 1-2 as a bridge to transplantation: pushing the limits?

The Synergy Micro-pump is the smallest implantable left ventricular assist device (LVAD) and provides partial flow support up to 4.25 L/min. It was shown that early intervention with this device can provide substantial benefits to patients with severe heart failure not yet sick enough for a full-support LVAD. However, as it can be inserted via small incisions with no need for sternotomy or cardiopulmonary bypass, it might be beneficial for selected high-risk patients. The aim of this study was to evaluate the efficacy of the Synergy Micro-pump in patients in INTERMACS class 1-2. From February 2012 to August 2013, 13 patients with severe heart failure were supported with the Synergy Pocket Micro-pump. Patients were divided into two groups according to INTERMACS class: the high-risk group (INTERMACS class 1-2) and the low-risk group (INTERMACS class 3-4). There were seven patients in INTERMACS class 1-2 and six in INTERMACS class 3-4. Patient demographics, perioperative characteristics, and postoperative outcomes were compared. There were no statistically significant differences in patient demographics, and mean support time was 108 ± 114 days in the high-risk group and 238 ± 198 days in the low-risk group. Also, there were no significant differences in perioperative characteristics or in the rate of postoperative adverse events. The overall survival was comparable between the two groups (one late death in each group, log-rank P = 0.608). Two patients from the high-risk group were upgraded to a full-support LVAD (P = 0.462) after 65 ± 84.9 days of mean support. One patient from the high-risk group and two patients from the low-risk group were successfully transplanted (P = 0.559). The use of the Synergy Micro-pump in INTERMACS 1-2 patients is feasible and is associated with similar postoperative outcome as in patients in INTERMACS 3-4. Carefully selected patients with severe heart failure could benefit due to the small size of the pump; however, further studies and medium-term follow-up are required.

Carotid artery Doppler flow pattern after deep hypothermic circulatory arrest in neonatal piglets.

The mechanisms of cerebral injury after cardiac surgery in neonates are not clear. The aim of the study was the analysis of flow changes in the carotid artery of neonatal piglets after deep hypothermic circulatory arrest (DHCA). Eight neonatal piglets were connected to cardiopulmonary bypass (CPB) and underwent (i) cooling to 18°C core temperature within 30 min, (ii) DHCA for 90 min, and finally (iii) rewarming to 37°C after cross-clamp release (60 min of reperfusion). The blood flow was measured in the left carotid artery by an ultrasonic flow probe before CPB (baseline; T0 ), immediately after termination of reperfusion on CPB (T1 ), 30 min later (T2 ), and 60 min later (T3 ). Additionally, the pulsatility index and the resistance index were calculated and compared. Finally, the relationship between the carotid artery flow and the corresponding pressure at each time-point was compared. After termination of CPB (T1 ), the mean carotid artery flow was reduced from 45.26 ± 2.58 mL/min at baseline to 23.29 ± 2.58 mL/min (P < 0.001) and remained reduced 30 and 60 min later (P < 0.001 vs. baseline). Both the pulsatility index and the resistance index were increased after termination of reperfusion, with the maximum occurring 30 min after CPB end. In conclusion, the carotid artery Doppler flow in neonatal piglets was reduced after DHCA, while the indices of pulsatility and resistance increased.

Proteomics analysis of cardiac extracellular matrix remodeling in a porcine model of ischemia/reperfusion injury.

BACKGROUND: After myocardial ischemia, extracellular matrix (ECM) deposition occurs at the site of the focal injury and at the border region. METHODS AND RESULTS: We have applied a novel proteomic method for the analysis of ECM in cardiovascular tissues to a porcine model of ischemia/reperfusion injury. ECM proteins were sequentially extracted and identified by liquid chromatography tandem mass spectrometry. For the first time, ECM proteins such as cartilage intermediate layer protein 1, matrilin-4, extracellular adipocyte enhancer binding protein 1, collagen α-1(XIV), and several members of the small leucine-rich proteoglycan family, including asporin and prolargin, were shown to contribute to cardiac remodeling. A comparison in 2 distinct cardiac regions (the focal injury in the left ventricle and the border region close to the occluded coronary artery) revealed a discordant regulation of protein and mRNA levels; although gene expression for selected ECM proteins was similar in both regions, the corresponding protein levels were much higher in the focal lesion. Further analysis based on >100 ECM proteins delineated a signature of early- and late-stage cardiac remodeling with transforming growth factor-ß1 signaling at the center of the interaction network. Finally, novel cardiac ECM proteins identified by proteomics were validated in human left ventricular tissue acquired from ischemic cardiomyopathy patients at cardiac transplantation. CONCLUSION: Our findings reveal a biosignature of early- and late-stage ECM remodeling after myocardial ischemia/reperfusion injury, which may have clinical utility as a prognostic marker and modifiable target for drug discovery.

Low-output is not the cause of death of neonatal piglets early after cardiopulmonary bypass.

The mortality rate of neonatal piglets after heart surgery is high. Searching for a possible explanation for the death of neonatal piglets early after cardiopulmonary bypass, we analyzed hemodynamic parameters regarding survival and non-survival. Initially, 10 neonatal piglets (younger than 7 days) were connected to cardiopulmonary bypass (CPB). The mean body weight was 2.98 ± 0.44 kg. Exposure of the heart was performed through a median sternotomy. After connection to the CPB, the piglets were cooled to 32°C core temperature before the ascending aorta was cross-clamped and the heart arrested (90 min). Thereafter, piglets were re-warmed to 37°C and separated from CPB. During follow-up, the piglets did not receive inotropic support or vasopressors. Piglets who survived at least 2 h after termination of CPB were included in the study for further data analysis (n = 9). Five piglets died 2.5 to 4.0 h (median: 3.5 h) after CPB; these piglets formed the non-survivors group. Four animals survived the complete follow-up of 6 h after CPB and formed the survivors group. Regarding contractility (dP/dt(max) , dP/dt(max) /P, and wall thickening) there were not statistically significant differences between the groups. Non-survivors showed prolonged decrease of mean arterial pressure of more than 20% of baseline values, corresponding with a value of below 30 mm Hg. In conclusion, the death of neonatal piglets early after cardiopulmonary bypass was not determined by low output.

The effect of cardiopulmonary bypass and hypothermic circulatory arrest on hepatic histology in newborn animals: an experimental study.

Still little is known about the effect of cardiac surgery on neonatal hepatic tissue. We examined the effect of cardiopulmonary bypass (CPB) and the effect of deep hypothermic circulatory arrest (DHCA) on neonatal hepatic tissue. Liver biopsies of neonatal piglets were taken after CPB (n = 4), after DHCA (n = 5), and after surgery without CPB (non-CPB; n = 3). Additionally, findings were compared to those of control piglets (n = 9). The liver specimens were fixed, stained with hematoxylin and eosin, and scored regarding inflammatory reaction, hepatocellular edema, and apoptosis. Inflammation score of treated groups was higher than in control; CPB 2.5 ± 0.5, DHCA 1.6 ± 0.4, non-CPB 1.2 ± 0.6, control 0.4 ± 0.3 (P < 0.001 CPB and DHCA vs. control; P < 0.05 non-CPB vs. control). Hepatic cell edema was more evident after DHCA (score 2.0 ± 0.4 vs. 0.2 ± 0.3 in control and 0.6 ± 0.5 after CPB; P < 0.001 and P < 0.05, respectively). The highest apoptotic cell count was in the non-CPB group (22.3 ± 6.3 vs. 11.4 ± 3.6 in control and 8.9 ± 5.4 after CPB; P < 0.05). The present study showed that (i) surgical trauma induces hepatic cell apoptosis; (ii) CPB increases hepatic inflammatory reaction; and (iii) DHCA amplifies hepatic cell edema.

Carotid Doppler flow after cardiopulmonary bypass and mild hypothermia in neonatal piglets.

Although the mechanisms of neurological disorders after cardiac surgery in neonates are still not fully understood, alterations in blood flow after cardiopulmonary bypass (CPB) may lead to cerebral injury. The aim of the study was the analysis of flow changes in the carotid artery of neonatal piglets after CPB. Ten neonatal piglets (younger than 7 days) were connected to the CPB and further management underwent three steps: (i) cooling to 32°C core temperature within 30 min; (ii) cardiac arrest under cardioplegic myocardial protection for 90 min; and (iii) rewarming to 37°C after cross-clamp release (60 min of reperfusion). In summary, piglets were separated from CPB after a total duration time of 180 min. The blood flow was measured in the left carotid artery by an ultrasonic flow probe before CPB (baseline), immediately after CPB, 30 min, and 60 min after CPB. Additionally, the pulsatility index and the resistance index were calculated and compared. Finally, the relation of the carotid artery flow data with the corresponding pressure data at each time point was compared. After termination of CPB, the carotid artery mean flow was reduced from 28.34 ± 13.79 mL/min at baseline to 20.91 ± 10.61 mL/min and remained reduced 30 and 60 min after CPB termination (19.71 ± 11.11 and 17.64 ± 15.31 mL/min, respectively). Both the pulsatility and the resistance index were reduced immediately after CPB termination and increased thereafter. Nevertheless, values did not reach statistical significance. In conclusion, the carotid Doppler flow immediately after CPB and mild hypothermia in neonatal piglets was lower than before CPB due to reduced vascular resistance. Additionally, the pressure-flow relation revealed that immediately after CPB, a higher pressure is required to obtain adequate flow.

A new device for intraoperative renal blood flow measurement during open-heart surgery: an experimental study and the clinical pilot study.

Renal blood flow (RBF) may vary during cardiopulmonary bypass and low flow may cause insufficient blood supply of the kidney triggering renal failure postoperatively. Still, a valid intraoperative method of continuous RBF measurement is not available. A new catheter combining thermodilution and intravascular Doppler was developed, first calibrated in an in vitro model, and the catheter specific constant was determined. Then, application of the device was evaluated in a pilot study in an adult cardiovascular population. The data of the clinical pilot study revealed high correlation between the flow velocities detected by intravascular Doppler and the RBF measured by thermodilution (Pearson's correlation range: 0.78 to 0.97). In conclusion, the RBF can be measured excellently in real time using the new catheter, even under cardiopulmonary bypass.

Incidence of deep sternal wound infection is not reduced with autologous platelet rich plasma in high-risk cardiac surgery patients.

BACKGROUND: Deep sternal wound infections (DSWI) remain a devastating complication in cardiac surgery applying full sternotomy. As the risk profile in cardiac surgery changed toward an older and sicker population, the incidence of DSWI increases. Platelet rich plasma (PRP) holds promise in tissue regeneration with respect to bone regeneration, reduction of bleeding, and accelerated wound healing. The effect of PRP on DSWI was investigated in high-risk patients undergoing cardiac surgery with full sternotomy. METHODS: 196 consecutive patients at risk of DSWI were randomized to application of autologous PRP before sternal wiring (n = 97) or control (n = 99). All patients underwent cardiac surgery on cardiopulmonary bypass with cardioplegic cardiac arrest. Endpoint was occurrence of DSWI requiring revision surgery. RESULTS: Demographic, intraoperative, and perioperative variables as well as risk factors were comparable between groups. Incidence of DSWI was not different between the PRP-group and the control-group (6/97 (6.2%) vs. 3/99 (3.0%); n.s.). CONCLUSIONS: Local application of autologous PRP in cardiac surgery patients with full sternotomy at high risk for sternal complications did not reduce the incidence of DSWI.

Treatment of cardiovascular implantable electronic device infection with daptomycin.

We describe a case of 83-year-old man who was admitted to our department for treatment of recurrent device-pocket infections. Our report shows that in a case of high-risk patient with a complicated cardiac implantable electric devices infection involving multidrug-resistent gram-positive pathogen, the application of daptomycin in combination with staged surgical therapy can be efficient and safe.

Myocardial contractility and relaxation after deep hypothermic circulatory arrest in a neonatal piglet model.

Cooling before circulatory arrest or ischemic arrest has been reported to influence myocardial performance in isolated neonatal hearts. The aim of the present study was to analyze indices of myocardial contractility and relaxation in an in vivo neonatal model after deep hypothermic circulatory arrest (DHCA). DHCA (18°C; DHCA group; n = 8) or mild hypothermic cardiopulmonary bypass ([MH-CPB] 32°C; MH-CPB group; n = 10) was applied in newborn piglets. After reperfusion (60 and 120 min), left ventricular dP/dt(max) increased in DHCA and MH-CPB, while-dP/dt(max) decreased slightly in DHCA and increased in MH-CPB. Nevertheless, the differences between the two groups did not reach statistical significance. In conclusion, left ventricular contractility remained stable after reperfusion following DHCA, to some degree at the expense of the diastolic function.

Cardiopulmonary bypass and its direct effects on neonatal piglet kidney morphology.

Renal failure after open heart surgery is a serious complication even in the pediatric population. The aim of the present study was to analyze morphological changes after cardiopulmonary bypass (CPB) surgery in a neonatal piglet model. The kidneys of newborn piglets sacrificed 6 h after CPB were examined (CPB; n = 4) regarding tubular dilatation, vacuole formation, leukocytic infiltration, epithelial destruction, and interstitial edema. Thereafter, the findings were compared with the morphology of normal (untreated) neonatal piglet kidneys (control; n = 4). All changes but the interstitial edema were statistically significant if compared with the normal renal tissue: tubular dilatation (CPB vs. control P < 0.05), vacuole formation (CPB vs. control P < .05), leukocytic infiltration (CPB vs. control P < 0.05), and epithelial destruction (CPB vs. control P < 0.001). In conclusion, CPB induces significant changes in the morphology of the neonatal piglet kidneys.

Indications for reoperation late after correction of tetralogy of Fallot.

OBJECTIVE: Correction of tetralogy of Fallot has excellent long-term results. The present retrospective study investigates the indications for reoperation late after corrective surgery. METHODS: Data from 914 consecutive cases who underwent correction of tetralogy of Fallot in our department between 1960 and 2002 were retrospectively reviewed and analysed. In 91 patients, a total of 102 reoperations were performed late after repair. RESULTS: The mean time interval between corrective surgery and the first reoperation was 12.8 years. The main indication for reoperation was residual ventricular septal defect in nearly half of the cases, mostly isolated, but also in combination with a right ventricular outflow tract aneurysm or pulmonary stenosis. One-fourth of reoperated patients underwent a procedure on their pulmonary artery or pulmonary valve: replacement of pulmonary valve, replacement of primary implanted pulmonary artery conduits with or without concomitant surgery, and surgery for isolated peripheral pulmonary stenosis. The remaining indications were right ventricular outflow tract aneurysms and others. Aneurysms of the right ventricular outflow tract were seen mostly after the use of autologous - untreated - pericardial patch in 18 of 21 cases. CONCLUSION: The number of reoperations for residual ventricular septal defect decreased during the study period. The primary use of conduits led to an increased number of reoperations for conduit exchange due to degeneration or failure. Use of an untreated autologous pericardial patch for enlargement of the right ventricular outflow tract should be avoided due to increased risk for aneurysm formation.

Modified aortic cannulation for cardiopulmonary bypass in neonatal piglet model.

Animal models are still essential for studying effects of cardiopulmonary bypass. We describe modifications in cannulation technique for a neonatal piglet model, which may also serve as an "everyday" technique in congenital cardiac surgery (age of animals <7 days; mean body weight 2.9 +/- 0.5 kg). Surgical approach through median sternotomy and cardiopulmonary bypass was established by cannulating right atrium and ascending aorta with a modified aortic root cannula. Left ventricular venting was performed placing a cannula into the apex and connecting this to the venous drainage line. The described technique has been applied in 19 cases, all but one were without technical problems.

Risk and Outcome after Simultaneous Carotid Surgery and Cardiac Surgery: Single Centre Experience.

OBJECTIVE: Carotid artery stenosis in patients undergoing open-heart surgery may increase risk and deteriorate outcome. The aim of the study was the analysis of risks and outcome after simultaneous carotid and cardiac surgery. METHODS: We retrospectively reviewed the medical records of 100 consecutive patients who underwent simultaneous carotid surgery and open-heart surgery during a 5-year period (from 2006 to 2010). Seventy patients were male and 30 female; the mean age was 70.9±7.9 years (median: 71.8 years). Seventy-three patients underwent coronary bypass grafting (CABG), 18 patients combined CABG and valve procedures, 7 patients CABG combined with other procedures, and 3 patients isolated valve surgery. More than half of patients had had bilateral carotid artery pathology (n=51) including contralateral carotid artery occlusion in 12 cases. RESULTS: Carotid artery patch plasty was performed in 71 patients and eversion technique in 29. In 75 cases an intraluminal shunt was used. Thirty-day mortality rate was 7% due to cardiac complications (n=5), metabolic disturbance (n=1), and diffuse cerebral embolism (n=1). There were no carotid surgery-related deaths. Postoperatively, transient cerebral ischemia occurred in one patient and stroke with mild permanent neurological deficit (Rankin level 2) in another patient. CONCLUSION: Simultaneous carotid artery surgery and open-heart surgery have low risk. The underlying cardiac disease influences outcome.

Apigenin Reduces NF-κB and Subsequent Cytokine Production as Protective Effect in a Rodent Animal Model of Lung Ischemia-Reperfusion Injury.

PURPOSE: Lung ischemia-reperfusion injury (LIRI) can complicate lung transplantation or cardiac surgery with cardiopulmonary bypass, increasing morbidity and mortality. In LIRI, pro-inflammatory cytokines are activated, reactive oxygen species are generated and nuclear factor-κB (NF-κB) is up-regulated, altering lung mechanics. We tested the effect of the flavonoid apigenin on a rodent model of LIRI. METHODS: Thirty-seven Wistar rats were subjected to LIRI with or without a single or double dose of apigenin. Induction of LIRI involved sternotomy and clamping of either the left lung hilum or the pulmonary artery alone for 30 min, followed by 60 min of reperfusion. Control groups consisted of LIRI plus NaCl, a sham group and a baseline group. At the end of the experiments, both lungs were analyzed by RT-PCR, Western blot, and light microscopy. RESULTS: In placebos, the expression levels of pro-inflammatory markers were increased in both lungs significantly, whereas NF-κB was markedly up-regulated. Administration of apigenin reduced the activation of NF-κB and the expression of TNFα, iNOS, and IL-6. These effects were observed in total lung ischemia. Histology showed greater hemorrhage and exudation in the pulmonary periphery of all groups, whereby damage was practically absent in the central lung regions of the apigenin animals. A second dose of apigenin did not outclass a single one. CONCLUSIONS: We conclude that apigenin given intraperitoneally can reduce activation of NF-κB and also attenuate the expression of TNFα, IL-6, and iNOS in a surgical model of LIRI. The surgical procedure itself can induce significant damage to the lungs.

Is there a correlation between late re-exploration after cardiac surgery and removal of epicardial pacemaker wires?

BACKGROUND: Re-exploration for bleeding accounts for increased morbidity and mortality after major cardiac operations. The use of temporary epicardial pacemaker wires is a common procedure at many departments. The removal of these wires postoperatively can potentially lead to a serious bleeding necessitating intervention. METHODS: From Jan 2011 till Dec 2015 a total of 4244 major cardiac procedures were carried out at our department. We used temporary epicardial pacemaker wires in all cases. We collected all re-explorations for bleeding and pericardial tamponade from our surgical database and then we focused on the late re-explorations, meaning on the 4th postoperative day and thereafter, trying to identify the removal of the temporary pacemaker wires as the definite cause of bleeding. Patients' records and medication were examined. RESULTS: Thirty-nine late re-explorations for bleeding, consisting of repeat sternotomies, thoracotomies and subxiphoid pericardial drainages, were gathered. Eight patients had an acute bleeding incidence after removal of the temporary wires (0.18%). In four of these patients, a pericardial drainage was inserted, whereas the remaining patients were re-explorated through a repeat sternotomy. Two patients died of the acute pericardial tamponade, three had a blood transfusion and one had a wound infection. Seven out of eight patients were either on dual antiplatelet therapy or on combination of aspirin and vitamin K antagonist. CONCLUSIONS: A need for re-exploration due to removal of the temporary pacemaker wires is a very rare complication, which however increases morbidity and mortality. Adjustment of the postoperative anticoagulation therapy at the time of removal of the wires could further minimize or even prevent this serious complication.

Prevention of TNFalpha-associated myocardial dysfunction resulting from cardiopulmonary bypass and cardioplegic arrest by glucocorticoid treatment.

OBJECTIVE: Cardiac surgery on cardiopulmonary bypass (CPB) results in progressive myocardial dysfunction, despite unimpaired coronary blood flow, and is associated with increased myocardial tumor necrosis factor-alpha (TNFalpha) expression. We investigated whether anti-inflammatory treatment prevents increased TNFalpha expression and myocardial dysfunction after CPB. METHODS AND RESULTS: Baseline systemic hemodynamics, myocardial contractile function, aortic and coronary blood flow were measured in anesthetized pigs. Then, placebo (PLA; saline; n=7) or methylprednisolone (MP; 30 mg/kg; n=6) was infused intravenously and CPB was instituted. Global ischemia was induced for 10 min by aortic cross-clamping, followed by 1 h of cardioplegic cardiac arrest. After declamping and reperfusion, CPB was terminated after a total of 3 h. Measurements were repeated at 15 min, 4 h, and 8 h following termination of CPB. Systemic TNFalpha-plasma concentrations and left ventricular TNFalpha expression were analyzed. With unchanged coronary blood flow in both groups, a progressive loss of myocardial contractile function to 38+/-2% of baseline (p<0.01) and cardiac index to 48+/-6% of baseline (p<0.01) at 8 h after CPB in PLA was attenuated in MP (myocardial function: 72+/-3%, p<0.01 vs PLA; cardiac index: 78+/-6%, p<0.05 vs PLA). Systemic TNFalpha was increased at 8 h in PLA compared to MP (243+/-34 vs 90+/-34 pg/ml, p<0.05). Myocardial TNFalpha was increased at 8 h after CPB compared to baseline and MP (p<0.05). Myocardial TNFalpha immunostaining was more pronounced in PLA than in MP (p<0.05), with TNFalpha-mRNA localization predominantly to cardiomyocytes. CONCLUSIONS: Methylprednisolone attenuates both systemic and myocardial TNFalpha increases and progressive myocardial dysfunction induced by cardiac surgery, suggesting a key role for TNFalpha.

Surgical Myectomy after Failed Ablation for Hypertrophic Obstructive Cardiomyopathy.

Background Hypertrophic cardiomyopathy is a genetic disease of the myocardial sarcolemma characterized by left ventricular hypertrophy. When obstruction to the left ventricular outflow tract is present and symptoms are refractory to medication, surgical myectomy or alcohol septal ablation is indicated. Case Description We report a case of a patient presented for myectomy due to recurrence only 1 year after alcohol ablation. Interesting findings were a firm subaortic membrane and a direct insertion of the papillary muscle into the mitral valve. Conclusion After myectomy and extensive papillary muscle mobilization, a significant relief of obstruction was achieved.