Jakub Marczak

Is remote ischaemic preconditioning of benefit to patients undergoing cardiac surgery

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether remote ischaemic preconditioning (RIPC) is of benefit to patients undergoing cardiac surgery. Altogether, more than 264 papers were found using the reported search, 16 of which represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. We conclude that RIPC is a safe protocol which could potentially be used in cardiac surgery to provide additional cardiac protection against ischaemia reperfusion injury, although it may not be appropriate for patients on K(+) ATPase channel blockers (sulphonylureas) as they seem to eliminate the effect of RIPC. In our study, we found two meta-analyses of cardiac surgery with or without RIPC. Both unequivocally showed 0.81 and 0.74 standardized mean reduction in myocardial necrosis markers in patients receiving RIPC and cardiac or vascular surgery. No difference in perioperative myocardial infarction incidence or 30-day mortality were found. In adult cardiac surgery, we found 11 randomized control trials (RCTs) ranging in size from 45 to 162 patients. Two representative studies reported no difference in postoperative cardiac troponin I concentration in RIPC vs. controls. In one of the studies (CABG ± RIPC) no additional benefit could have been observed for RIPC regarding intra-aortic balloon pump usage (controls 8.5 vs. RIPC 7.5%), inotropic support (39 vs. 50%) or vasoconstrictor usage (66 vs. 64%). On the other hand, in the other study [CABG ± AVR (aortic valve replacement) ± RIPC] significant reduction of troponin I at 8 h postoperatively (controls, 2.90 µg/l vs. RIPC, 2.54 µg/l, P = 0.043) was shown. Marked reduction in cardiac necrosis markers was also found in several smaller RCTs concerning coronary artery bypass grafting (CABG) patients receiving RIPC preoperatively: with cold crystalloid cardioplegia (44.5% reduction), with cross-clamping and fibrillation (43% reduction) and with cold blood cardioplegia (42.4% reduction). The proof of concept trials summarized here give some early evidence that RIPC may potentially provide some reduction in myocardial injury. If confirmed, in future clinical studies this technique may one day lead to a method to reduce reperfusion injury in clinical practice.

Is thoracoscopic patent ductus arteriosus closure superior to conventional surgery

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether thoracoscopic patent ductus arteriosus (PDA) closure is superior to conventional surgery. Altogether 821 papers were found using the reported search, 11 of which represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Eleven studies included in the analysis consisted of two prospective and three retrospective, non-randomized studies and six case series. Four included studies focused only on preterm infants, three studies enrolled neonates and the other four analysed all age groups from neonates to older children or young adults. There were no differences in mortality between video-assisted thoracoscopic surgery (VATS) and conventional surgery. Two studies suggested that VATS offers shorter operative times. Two papers observed shorter hospital stay, although the other two noted no significant difference. A large prospective trial found VATS to be associated with a lower number of postoperative complications in neonates and infants, whereas other studies suggested no significant differences in short-term postoperative complications. There is little evidence to suggest better musculoskeletal status and cosmesis in neonates following VATS. Conversion from thoracoscopy to thoracotomy described in six papers was seldom and it did not lead to any additional complications. All observational studies confirmed that both techniques are free from major adverse cardiovascular complications and these two techniques can be safely used in all patients qualified for surgical PDA closure. Two studies compared cost-effectiveness between the two techniques; one of them described VATS as significantly more cost-efficient, whereas the other study observed no difference. However, it should be noted that data were provided from different countries and time periods. The results presented suggest that there are no significant differences in early clinical outcomes between VATS and thoracotomy in all age groups. However, where differences have been shown, such as pain, postoperative complications, length of hospital and ICU stay and cost, these favour the VATS approach.

Electroporation-induced changes in normal immature rat myoblasts (H9C2)

Application of a high electric field causes an electric shock to the heart. This is utilized in defibrillation to reestablish normal contraction rhythms during dangerous arrhythmias or in cardiac arrest. If shock-induced transmembrane potentials are large enough, they can cause tissue destruction due to irreversible electroporation (EP). Also electrochemotherapy of nearby tissues may have an adverse effect on the heart. Herein, we present experimental data on effects of electroporation in culture of cardiac cells (H9C2). The electric field was applied in short pulses of 25-3250 V/cm, 50 µs each. The viability of cells was tested by MTT assay after 24 hours. For detection of DNA fragmentation, associated with apoptosis, alkaline and neutral comet assays were performed after EP. Additionally phase contrast images of cells obtained directly after EP were analyzed. Although cell images indicated disruption of cell membranes after EP with high intensities, only a few percent of apoptotic cells and no necrotic effects in the cell nucleus could be observed in comet assay tests performed 2 hours post EP. MTT viability test showed that pulse intensities above 375 V/cm are destructive for myocytes viability.

What is the impact of preoperative aspirin administration on patients undergoing coronary artery bypass grafting

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether continuation of administration of preoperative aspirin until the day of coronary artery bypass grafting (CABG) could minimize postoperative mortality, prevalence of postoperative myocardial infarction (MI) with or without influence on postoperative bleeding, packed red blood cell (PRBC) transfusion and reoperation for bleeding. Altogether, 662 papers were found using the reported search, 7 of which represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Seven studies, included in this review, consisted of five meta-analyses and two randomized controlled trials. One meta-analysis, involving 27 533 patients submitted to CABG, showed that the administration of preoperative aspirin decreased postoperative 30-day mortality by 27%. Another meta-analysis, including 1437 patients, showed that preoperative aspirin decreased the incidence of perioperative MI by 44%, the effect being even more pronounced with low-dose aspirin, which reduced the prevalence of perioperative MI by 63%. One RCT showed that preoperative aspirin is associated with reduced long-term hazard of MI or repeated revascularization. Four meta-analyses and two RCTs showed that preoperative aspirin is associated with increased postoperative bleeding, PRBC transfusion and reoperation for bleeding. However, this was not the case with preoperative administration of low-dose aspirin. The results presented in these studies suggest that preoperative aspirin administration in patients undergoing CABG has a significant benefit in reducing the incidence of perioperative MI and 30-day mortality rate, as well as reduced long-term hazard of MI or repeated revascularization. At a higher dose (>100 mg/day), postoperative bleeding, PRBC transfusion and reoperation for bleeding increased. However, with low-dose aspirin (≤100 mg/day), these benefits were not at the expense of increased postoperative bleeding or transfusion.

Preoperative Aspirin Therapy Reduces Early Mortality in Patients Undergoing Cardiac Surgery

We read with interest the study performed by Ma and associates, which failed to demonstrate any impact on the 30-day, all-cause mortality in patients receiving aspirin (ASA) prior to coronary artery bypass grafting (CABG). However, recent studies have shown that the preoperative administration of ASA may be of benefit not only to patients undergoing CABG but also to patients undergoing other cardiac procedures. In order to determine whether a preoperative ASA continuation has any impact on the 30-day, all-cause mortality, we performed an updated meta-analysis of preoperative ASA use in patients undergoing all cardiac surgical procedures. Current through May 2015, all articles concerning preoperative ASA and postoperative all-cause mortality were identified through OVID SP and a manual search of MEDLINE, EMBASE, and COCHRANE Central Registry of Controlled Trials. The exclusion criteria were as follows: the use of clopidogrel, dipyridamole, integrilin, ticagrelor, heparin, or vitamin K antagonists prior to the surgery; age less than 18; studies using per-protocol analysis; and those not presenting mortality within 30 days following surgery. Finally, 17 trials (12 observational nonrandomized and 5 randomized controlled trials) comparing patients undergoing cardiac surgery, in whom preoperative ASA had been continued until the surgery, with patients in whom aspirin had been withdrawn no less than 7 days prior to the surgery or who had been randomized to receive placebo, were included. Presented analysis involved altogether 30 786 patients, the majority of whom underwent CABG (89.4%, n 1⁄4 27 533), while the remaining underwent valve surgery (4.9%, n 1⁄4 1523), CABG with concomitant valve surgery (3.1%, n 1⁄4 982), or other cardiac procedures (2.4%, n 1⁄4 748). Pooled analysis showed a 27% statistically significant reduction in 30-day all-cause mortality in patients receiving ASA preoperatively (odds ratio: 0.73 [95%confidence interval: 0.57-0.94]; P 1⁄4 .0127; Figure 1). There was no significant between-studies heterogeneity (I 1⁄4 11.51%, Q 1⁄4 19.21, P 1⁄4 .32). No difference was seen on a fixed-effect analysis, neither when any single study was omitted. Our analysis differs from the previous report in 2 aspects. First, it involves patients undergoing all cardiac procedures with the great majority receiving CABG. Second, it gathers the most up-to-date evidence. Despite the results of Ma et al, we conclude that there might be an approximately 30% reduction in mortality in patients undergoing cardiac surgery when using ASA within the 7 days preoperatively. Most of the included patients underwent CABG (92.5%), therefore preoperative continuation of ASA may reduce 30-day mortality in patients undergoing surgical coronary revascularization. Although there is a statistically significant reduction in early mortality in our analysis, this conclusion is substantially limited by the absence of any support from the randomized controlled trials and the sole reliance on nonhypothesis testing, nonrandomized observational studies. In this letter, we do not address the bleeding risk reports by Ma et al, with preoperative aspirin use in patients undergoing cardiac surgery. We should thus await conclusive results of large, well-powered randomized clinical trials and a careful risk–benefit analysis of an early mortality benefit, despite any excess bleeding risk before forming any judgments or making recommendations to use preoperative aspirin in patients undergoing cardiac surgery.

Surgical closure of patent ductus arteriosus in extremely low birth weight infants weighing less than 750 grams

BACKGROUND Patent ductus arteriosus (PDA) occurs more frequently in premature infants. Depending on the degree of prematurity, these children often have other serious comorbidities that could have a significant impact on surgical outcome. AIM This study aimed to evaluate the clinical results of surgical ligation of PDA in extremely low body weight preterm infants with birth weight below 750 g, and to identify risk factors of mortality. METHODS A total of 31 preterm infants with birth weight below 750 g and significant PDA were operated between 2006 and 2016 through posterolateral thoracotomy (n = 16) or with the use of video-assisted thoracoscopic method (n = 15). Mean weight at the time of surgery was 750.8 ± 104.7 g. The gestational age ranged from 22 to 32 weeks. Data were retrospectively analysed, and prospective 100% follow-up was performed. RESULTS In-hospital mortality was 25.8% (n = 8). The type of surgery had no influence on the results. During the follow-up period lasting 5.2 ± 2.5 years, two other patients died. One-year and five-year probability of survival was 77.4% and 74.2%, respectively. The predominant cause of death was acute heart failure. All patients with preoperative renal dysfunction died in the postoperative period. Moreover, Cox regression analysis revealed renal dysfunction as an independent risk factor of early death. CONCLUSIONS Preterm infants with birth weight less than 750 g and significant PDA are highly challenging patients. Despite the recent advances in perioperative management with neonates, surgery is still associated with a high early mortality rate irrespective of the applied method.

Conversion to thoracotomy of video-assisted thoracoscopic closure of patent ductus arteriosus

Introduction Posterolateral thoracotomy was the access of choice in surgical treatment of patent ductus arteriosus (PDA) for many years before the introduction of video-assisted thoracoscopic surgery (VATS). The latter is thought to reduce postoperative pain and improve musculoskeletal system status. However, it carries a potential risk of conversion to thoracotomy. Aim To evaluate the rate, reasons and outcomes of VATS conversion to thoracotomy in surgical PDA patients. Material and methods From 2012 to 2017, 112 children were qualified for VATS closure of symptomatic PDA. Among them, 19 (16.9%) with the median age of 19.4 months required conversion to thoracotomy. The predominant reasons for conversion, early mortality and morbidity as well as late survival were evaluated. Results The overall conversion rate was 16.9% with an evident learning curve as it decreased significantly from more than 20% at the beginning to approximately 10% in the last 2 years. The predominant reasons were incomplete PDA closure (n = 6; 31.6%) followed by ductal bleeding after clip application (n = 5; 26.3%) and inadequate visualization (n = 5). One child died 48 h after the surgery due to acute cardiopulmonary failure (mortality 5.9%). All patients required postoperative chest tube insertion, and two of them developed postoperative pneumothorax. Neither deaths nor severe adverse events were noted throughout the follow-up period. Conclusions The rate of VATS PDA closure conversion to standard thoracotomy features a learning curve. Although it must be considered as a serious complication, probably it does not negatively affect either early the mortality rate or long-term survival.

Does patient–prosthesis mismatch have a negative impact on outcomes following mitral valve replacement?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether patient-prosthesis mismatch (PPM) has a negative impact on patients undergoing mitral valve replacement in terms of postoperative mortality, incidence of postoperative pulmonary hypertension (PH) and higher transmitral gradients. Altogether 103 papers were found using the reported search, 18 of which represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. Overall, 8 studies with a total of 4812 patients reported that PPM has a significantly negative impact on long-term mortality, whereas 5 studies with a total of 1558 patients reported no effect on mortality. One study with a total of 2440 patients reported preoperative PH as the risk factor for increased mortality in the presence of moderate or severe PPM. Three studies evaluated the effect of PPM on postoperative PH and reported that PPM was associated with significantly increased postoperative PH. The majority of the studies reported that PPM was associated with higher peak or mean transmitral gradient and systolic pulmonary artery pressure. The results presented in these studies suggest that PPM in patients undergoing mitral valve replacement was associated with increased postoperative mean and peak transmitral gradient and higher postoperative systolic pulmonary artery pressure. PPM may be associated with increased long-term mortality. Severe PPM was directly associated with increased long-term mortality when compared with moderate or no PPM. Evidence suggests that PPM is associated with increased incidence of postoperative PH.

Is administration of dual-antiplatelet therapy beneficial for patients following off-pump coronary artery bypass grafting?

A best evidence topic in cardiac surgery was written according to a structured protocol. The question addressed was whether administration of dual-antiplatelet therapy (DAPT) following off-pump coronary artery bypass grafting (OPCAB) would improve postoperative clinical outcomes or minimize the incidence of postoperative graft failure. In total, 101 papers were found using the reported search, 14 of which represented the best evidence to answer the clinical question. The authors, journal, date and country of publication, patient group studied, study type, relevant outcomes and results of these papers are tabulated. One meta-analysis and 3 randomized controlled trials showed that DAPT following OPCAB is associated with decreased incidence of saphenous vein graft occlusion. One randomized controlled trial and 4 observational studies showed no effect of DAPT on mortality following OPCAB, whereas 3 observational studies showed that DAPT decreased mortality. One meta-analysis and 4 observational studies showed that DAPT reduced the incidence of cardiac events following OPCAB. One randomized controlled trial and 4 observational studies showed that DAPT did not increase the incidence of major or minor bleeding complications following OPCAB. The results presented suggest that administration of DAPT in patients following OPCAB for at least 3 months improves saphenous vein graft patency and could be protective against recurrence of cardiac events, especially acute coronary syndrome, in comparison with aspirin monotherapy. The administration of DAPT following OPCAB is safe and is not associated with increased incidence of major or minor bleeding complications when compared with aspirin alone.

Thromboembolic complications after an ankle joint open fracture in a patient with a history of deep vein thrombosis in the lower limbs

A 55-year-old patient was admitted to the Department of Orthopedics due to an open fracture in the right ankle joint. On the seventh day of hospitalization the patient experienced a transient ischemic attack. During the next day, dyspnea, chest pain and a ‘rider’ type pulmonary embolism in the pulmonary trunk occluding both pulmonary arteries and its branches were diagnosed. The patient was transferred to the Department of Cardiac Surgery. He underwent pulmonary embolectomy for massive pulmonary, right and left atrial embolism, and left ventricular embolism. ASD II was closed during this procedure. Ultrasonography with Doppler was performed 6 days after the surgery and revealed deep vein thrombosis, so the patient was transferred to the Department of Vascular Surgery for temporary inferior vena cava filter placement at the time of orthopedic surgery. The next day after implantation of the filter, the lower limb was operated on, and 14 days after orthopedic surgery, the vena cava filter was removed.