Mini-extracorporeal circulation technology, conventional bypass and prime displacement in isolated coronary and aortic valve surgery: a propensity-matched in-hospital and survival analysis.

OBJECTIVES: Conventional cardiopulmonary bypass is the most commonly used means of artificial circulation in cardiac surgery. However, it suffers from the effects of haemodilution and activation of inflammatory/coagulation cascades. Prime displacement (PD) can offset haemodilution and mini-extracorporeal technology (MIECT) can offset both. So far, no study has compared all of these modalities together; hence, we compared the outcomes of these 3 modalities at our institution. METHODS: This was a retrospective analysis of our cardiac surgical database. A total of 9626 patients underwent conventional bypass (CB), 3125 patients underwent a modification of CB, called PD, and 904 underwent MIECT. A 1:1 propensity-matching algorithm was employed using IBM SPSS 24 to match (i) 813 MIECT patients with 813 CB patients and (ii) 717 MIECT patients with 717 PD patients. The patients included coronary artery bypass grafting and valve surgery. RESULTS: MIECT had significantly (P < 0.05) longer bypass and cross-clamp times compared to CB and PD. MIECT had significantly higher rates of postoperative atrial fibrillation associated with it compared to CB. The mean red cell blood transfusion was significantly lower in the MIECT group compared to the CB group as was the mean platelet transfusion and fresh frozen plasma transfusion. The overall 5-year survival was higher in the MIECT group compared to the CB group (log-rank, P = 0.018). Between the MIECT and the PD groups, we found the incidence of renal failure and gastrointestinal complications to be significantly higher in the PD group compared to the MIECT group. CONCLUSIONS: MIECT has short-term advantages over CB and PD. However, due to the retrospective limitations of the study, including calendar time bias, a multicentre randomized controlled trial comparing all 3 modalities will be beneficial for the larger cardiac community.

Complex aortic surgery in a regional center in the United Kingdom. Should the United Kingdom now adopt a United States-style supercenter model?

BACKGROUND: The United States has established aortic supercenters, which have demonstrated clear improvements in the short-term and long-term outcomes after surgery on the thoracic aorta. This model of care does not exist in the United Kingdom. We have looked at our recent experience of emergency and elective thoracic aortic surgery and describe and compare our operative outcomes and 10-year survival with other regional centers and supercenters worldwide. METHODS: This was a retrospective analysis of data collected prospectively from our cardiac database on patients who underwent surgery on the thoracic aorta (n=318) between November 1999 and November 2012. The outcome measures were adjusted operative mortality, postoperative complications, and long-term survival. RESULTS: Type A dissection was carried out on 23.90% of the patients and 76.10% had surgery on the aortic root and thoracic aorta for nondissection. The mean age of the patients was 62.21±14.1 years. The mean logistic EuroSCORE was 26 in the dissection group and 19 in the nondissection group. Hospital mortality was significantly greater (P<.05) in the dissection group compared with the nondissection group (23.7% vs 12.8%). Survival after dissection and nondissection surgery was 66.3%±5.6% versus 77.4%±2.8%, respectively, at 3 years, 63.9%±5.9% versus 71.8%±3.2% at 5 years, and 53.7%±7.4% versus 47.1%±6.0% at 10 years. CONCLUSIONS: Our outcomes are comparable with other regional centers worldwide; however, they are not as good as those reported from the aortic supercenters. There should be continued impetus regarding the establishment of thoracic aortic surgery guidelines and specialist aortic centers in the United Kingdom.

The effect of deep hypothermia on the human pulmonary circulation.

OBJECTIVE: Acute rises in pulmonary artery pressures following complex cardiac surgery are associated with high morbidity and mortality. We hypothesised that periods of deep hypothermia predispose to elevated pulmonary pressures upon rewarming. We investigated the effect of this hypothermic preconditioning on isolated human pulmonary arteries and isolated perfused lungs. METHODS: Isometric tension was measured in human pulmonary artery rings (n=24). We assessed the constriction and dilation of these arteries at 37 °C and 17 °C. Isolated perfused human lung models consisted of lobes ventilated via a bronchial cannula and perfused with Krebs via a pulmonary artery cannula. Bronchial and pulmonary artery pressures were recorded. We investigated the effect of temperature using a heat exchanger. RESULTS: Rewarming from 17 °C to 37 °C caused a 1.3 fold increase in resting tension (p<0.05). Arteries constricted 8.6 times greater to 30 nM KCl, constricted 17 times greater to 1 nM Endothelin-1 and dilated 30.3 times greater to 100 µM SNP at 37 °C than at 17 °C (p<0.005). No difference was observed in the responses of arteries originally maintained at 37 °C compared to those arteries maintained at 17 °C and rewarmed to 37 °C. Hypothermia blunted the increase in pulmonary artery pressures to stimulants such as potassium chloride as well as to H-R but did not precondition arteries to higher pulmonary artery pressures upon re-warming. CONCLUSIONS: Deep hypothermia reduces the responsiveness of human pulmonary arteries but does not, however, precondition an exaggerated response to vasoactive agents upon re-warming.