Venoarterial extracorporeal membrane oxygenation for postcardiotomy cardiogenic shock-A six-year service evaluation.

Only a small number of English hospitals provide postcardiotomy venoarterial extracorporeal membrane oxygenation (VA-ECMO) and there are doubts about its efficacy and safety. The aim of this service evaluation was to determine local survival rates and report on patient demographics. This was a retrospective service evaluation of prospectively recorded routine clinical data from a tertiary cardiothoracic center in the United Kingdom offering services including cardiac and thoracic surgery, heart and lung transplantation, venovenous extracorporeal membrane oxygenation (VV-ECMO) for respiratory failure, and all types of mechanical circulatory support. In six years, 39 patients were supported with VA-ECMO for refractory postcardiotomy cardiogenic shock (PCCS). We analyzed survival data and looked for associations between survival rates and patient characteristics. The intervention was venoarterial-ECMO in patients with PCCS either following weaning from cardiopulmonary bypass or following a trial of inotropes and intra-aortic balloon counterpulsation on the intensive care unit. 30-day, hospital discharge, 1-year and 2-year survivals were 51.3%, 41%, 37.5%, and 38.5%, respectively. The median (IQR [range]) duration of support was 6 (4-9 [1-35]) days. Nonsurvival was associated with advanced age, shorter intensive care length of stay, and the requirement for postoperative hemofiltration. Reasonable survival rates can be achieved in selected patients who may have been expected to have a worse mortality without VA-ECMO. We suggest postoperative VA-ECMO should be available to all patients undergoing cardiac surgery be it in their own center or through an established pathway to a specialist center.

The Wythenshawe Hybrid Circuit for lung transplantation: a previously undescribed circuit for lung transplant.

Extracorporeal membrane oxygenation is a safe modality of cardiorespiratory support for lung transplantation, with a reduction in coagulopathy and transfusion requirement when compared with cardiopulmonary bypass. In some scenarios, in lung transplantation, there are advantages to the use of cardiopulmonary bypass, which allows cardiac decompression, filtering of embolic air, easy addition and removal of volume, and a means to immediately reintroduce lost blood into circulation. We describe a novel circuit which allows safe and easy switch between modalities without prolonged interruption of flow. This circuit offers a safety net during surgery to minimise the risks influencing the use of extracorporeal membrane oxygenation.

Randomized Study Comparing the Effect of Carbon Dioxide Insufflation on Veins Using 2 Types of Endoscopic and Open Vein Harvesting.

OBJECTIVE: The aim of the study was to assess whether the use of carbon dioxide insufflation has any impact on integrity of long saphenous vein comparing 2 types of endoscopic vein harvesting and traditional open vein harvesting. METHODS: A total of 301 patients were prospectively randomized into 3 groups. Group 1 control arm of open vein harvesting (n = 101), group 2 closed tunnel (carbon dioxide) endoscopic vein harvesting (n = 100) and Group 3 open tunnel (carbon dioxide) endoscopic vein harvesting (open tunnel endoscopic vein harvesting) (n = 100). Each group was assessed to determine the systemic level of partial arterial carbon dioxide, end-tidal carbon dioxide, and pH. Three blood samples were obtained at baseline, 10 minutes after start of endoscopic vein harvesting, and 10 minutes after the vein was retrieved. Vein samples were taken immediately after vein harvesting without further surgical handling to measure the histological level of endothelial damage. A modified validated endothelial scoring system was used to compare the extent of endothelial stretching and detachment. RESULTS: The level of end-tidal carbon dioxide was maintained in the open tunnel endoscopic vein harvesting and open vein harvesting groups but increased significantly in the closed tunnel endoscopic vein harvesting group (P = 0.451, P = 0.385, and P < 0.001). Interestingly, partial arterial carbon dioxide also did not differ over time in the open tunnel endoscopic vein harvesting group (P = 0.241), whereas partial arterial carbon dioxide reduced significantly over time in the open vein harvesting group (P = 0.001). A profound increase in partial arterial carbon dioxide was observed in the closed tunnel endoscopic vein harvesting group (P < 0.001). Consistent with these patterns, only the closed tunnel endoscopic vein harvesting group demonstrated a sudden drop in pH over time (P < 0.001), whereas pH remained stable for both open tunnel endoscopic vein harvesting and open vein harvesting groups (P = 0.105 and P = 0.869, respectively). Endothelial integrity was better preserved in the open vein harvesting group compared with open tunnel endoscopic vein harvesting or closed tunnel endoscopic vein harvesting groups (P = 0.012) and was not affected by changes in carbon dioxide or low pH. Significantly greater stretching of the endothelium was observed in the open tunnel endoscopic open tunnel endoscopic vein harvesting group compared with the other groups (P = 0.003). CONCLUSIONS: This study demonstrated that the different vein harvesting techniques impact on endothelial integrity; however, this does not seem to be related to the increase in systemic absorption of carbon dioxide or to the pressurized endoscopic tunnel. The open tunnel endoscopic harvesting technique vein had more endothelial stretching compared with the closed tunnel endoscopic technique; this may be due to manual dissection of the vein. Further research is required to evaluate the long-term clinical outcome of these vein grafts.

The MDR1/ABCB1 gene, a high-impact risk factor for cardiac transplant rejection.

BACKGROUND: Variations in the expression and activity levels of the multidrug-resistance MDR1/ABCB1 encoded P- glycoprotein (P-gp) have an impact on the therapeutic efficacy of many drugs. C3435T and G2677 polymorphisms of the MDR1/ABCB1 gene correlate with cellular expression levels of P-gp, a membrane-bound efflux pump which removes a multitude of drugs, including chemotherapy drugs and immunosuppressants, from cells. We aimed to investigate whether the phenomenon of drug resistance, mediated by the MDR1/ABCB1 gene and seen in tumor cells to chemotherapeutic agents, is important in the field of transplantation, predisposing some patients to resistance to immunosuppressants. METHODS: G2677 and C3435T polymorphisms of the ABCB1 gene were determined by PCR in 170 heart transplant recipients. We examined the relationship between MDR1/ABCB1 polymorphisms and endomyocardial biopsy-proven rejection (EBPR) determined by biopsy performed at set intervals according to a standard protocol. RESULTS: A significant relationship was found between a patient's C3435T genotype and freedom from first grade > or =3A rejection episode. 3435-CC recipients were 1.8 times (1.05-3.09; P = 0.03) more likely to undergo a > or =3A rejection episode in the first 12 months. Haplotypes derived from the G2677 and C3435T polymorphisms (GG/CC, GT/CT and TT/TT) amplified this phenomenon further (log rank, P = 0.03; HR 2.18; 1.21-4.26; P = 0.02). CONCLUSIONS: ABCB1 polymorphisms correlate with freedom from grade > or =3A EBPR and we believe that this may be attributed to MDR1/ABCB1 encoded P-gp mediating the efflux of immunosuppressants out of leukocytes, with depleted immunosuppressant levels in leukocytes manifesting as increased cellular rejection.

A randomized study comparing traditional monofilament knotted sutures with barbed knotless sutures for donor leg wound closure in coronary artery bypass surgery.

OBJECTIVES: Surgical knots on the suture line provide an anchoring function, but also represent a potential source of infection and irritation on the donor leg after coronary artery bypass surgery. Knotless barbed sutures were designed to prevent knot-related complications. This study compared knot-related wound complication rates between patients receiving traditional monofilament sutures and those receiving barbed knotless sutures for closure of the donor leg. METHODS: One hundred and forty-two patients were randomized into two groups. Group 1 (n = 70) received traditional monofilament sutures and Group 2 (n = 72) received barbed knotless sutures. All wounds were assessed on postoperative days 3 and 5 and weeks 2, 4 and 6 using a validated wound scoring system. Antibiotics usage and general practitioner and district nurse visits were recorded. RESULTS: No demographic differences were observed between groups. Leg wound skin closure times were significantly shorter in Group 2 compared with Group 1 (P < 0.001). Group 1 demonstrated a greater incidence of excessive scarring (P < 0.001), itching (P < 0.001), irritation (P < 0.001) and adverse skin tissue reactions (P < 0.001) than Group 2. Fewer general practitioner visits were recorded in Group 1 compared with Group 2 (P = 0.051). CONCLUSION: Knotless barbed suture usage significantly reduces the incidence of knot-related leg wound complications compared with traditional monofilament knotted sutures. This may be related to differences in the rate of absorption of the suture material or an associated decrease in the incidence of adverse skin tissue reactions that may delay postoperative wound healing.

Size matching in lung transplantation: an evidence-based review.

The evidence base for size matching between donors and recipients in lung transplantation has not recently been reviewed in a comprehensive manner. Our aim in this study was to assimilate published studies that have addressed size matching of donors to recipients and to establish a pragmatic understanding of the range of lung sizes that may be used for lung transplantation. A comprehensive literature search was performed using Medline and PubMed up to and including September 2012, to identify scientific articles that relate to size matching between donors and lung transplant recipients. Seventy-two articles were identified, of which 21 had addressed the question of the impact of size mismatching on outcomes in lung transplantation. No study has specifically tested the consequences of intentionally mismatching above or below the hypothetical limits for double lung transplantation of a predicted total lung capacity for the donor of between 75% and 125% of the recipient predicted total lung capacity as set out in the ISHLT consensus report on lung donor acceptability criteria. Research is lacking that has robustly defined limits for size mismatch for single lung transplantation and for recipients with restrictive lung pathologies such as pulmonary fibrosis. Published research on the impact of size mismatching between lung transplant donors and recipients is limited by study design and size. It is centered on addressing the issue of mismatch in double lung transplantation in cohorts with a diagnostically heterogeneous make-up and in single lung transplant patients with chronic obstructive pulmonary disease.

Mid-term outcomes for Endoscopic versus Open Vein Harvest: a case control study.

BACKGROUND: Saphenous vein remains the most common conduit for coronary artery bypass grafting with increasing uptake of minimally invasive harvesting techniques. While Endoscopic Vein Harvest (EVH) has been demonstrated to improve early morbidity compared to Open Vein Harvest (OVH), recent literature suggests that this may be at the expense of graft patency at one year and survival at three years. METHODS: We undertook a retrospective single-centre, single-surgeon, case-control study of EVH (n = 89) and OVH (n = 182). The primary endpoint was death with secondary endpoints including acute coronary syndrome, revascularisation or other major adverse cardiac events. Freedom from angina, wound complications and self-rated health status were also assessed. Where repeat angiography had been performed, this was reviewed. RESULTS: Both groups were well matched demographically and for peri-operative characteristics. All cause mortality was 2/89 (2%) and 11/182 (6%) in the EVH and OVH groups respectively. This was shown by Cox Log-Rank analysis to be non-significant (p = 0.65), even if adjusting for inpatient mortality (p = 0.74). There was no difference in the rates of freedom from angina (p = 1.00), re-admission (p = 0.78) or need for further anti-anginals (p = 1.00). There was a significant reduction in the incidence of leg wound infections and complications in the endoscopic group (EVH: 7%; OVH: 28%; p = 0.0008) and the skew of high patient self-rated health scores in the EVH group (61% compared to 52% in the open group) approached statistical significance (p = 0.06). CONCLUSIONS: While aware of the limitations of this small retrospective study, we are heartened by the preliminary results and consider our data to be justification for continuing to provide patients the opportunity to have minimally invasive conduit harvest in our centre. More robust evidence is still required to elucidate the implications of endoscopic techniques on conduit patency and patient outcome, but until the results of a large, prospective and randomised trial are available, we believe we can confidently offer our patients the option and benefits of EVH.

Tumor necrosis factor alpha influences the inflammatory response after coronary surgery.

BACKGROUND: A systemic inflammatory response is not uncommonly observed after coronary revascularization. Tumor necrosis factor alpha is one of a number of modulators of this response. A functional polymorphism within the TNFalpha gene at position G-308A has been associated with increased TNFalpha levels. The relationship between predicted TNFalpha genotype and circulating TNFalpha levels in patients undergoing coronary revascularization surgery has yet to be defined. We examined the relationship between TNFalpha G-308A polymorphism, TNFalpha postoperative levels, and clinical outcome after coronary revascularization surgery. METHODS: We obtained DNA from 96 consecutive patients who underwent elective coronary revascularization. Patients were genotyped for TNFalpha G-308A polymorphism using sequence specific primer-polymerase chain reaction (SSP-PCR). Tumor necrosis factor alpha levels were measured on serum samples taken 3 hours postoperatively using enzyme-linked immunosorbent assay (ELISA). RESULTS: The prevalence of AA, AG, and GG TNFalpha-308 genotype was 12%, 40%, and 48%, respectively. Patients homozygous for A had higher circulating levels of TNFalpha (p = 0.009). Higher levels of TNFalpha were significantly associated with prolonged intensive care unit stay (p = 0.008), increase usage of an inotropic agent (p = 0.024), increased mortality risk (p = 0.018), and diabetes (p = 0.019). These remained statistically significant after risk stratification. CONCLUSIONS: Patients of the AA-308 TNFalpha genotype showed significantly higher TNFalpha plasma levels. Higher plasma levels of TNFalpha were associated with less favorable outcome after coronary revascularization surgery. It may prove useful to utilize TNFalpha serum levels as a marker for identifying high-risk patients in the future.

Should the pericardium be closed in patients undergoing cardiac surgery?

A best evidence topic in Cardiothoracic Surgery was written according to a structured protocol. The question addressed was in open heart surgery is there any adverse effect to closing the pericardium? Altogether 240 publications were found using the reported search of which 8 were deemed to be relevant to answer the clinical question. The author, journal, date and country of publication, patient group studied, study type, relevant outcomes, results, and study weaknesses of these papers are tabulated. We conclude that the adverse haemodynamic impact of pericardial closure is confirmed in several studies, however, no study has yet reported an adverse clinical outcome due to the closure of the pericardium.