The Glasgow Experience of Extended Myocardial Protection: A Novel Method of Implantation to Reduce Primary Graft Dysfunction After Heart Transplant.

OBJECTIVES: Around 2000 heart transplants are performed in Europe annually. The rates of primary graft dysfunction in Europe are among the highest in the world. With increasing demand for organs and the limited supply of donors, novel techniques such as ex vivo normothermic perfusion have garnered incre-asing interest. We present a series of patients who underwent heart transplant at our unit in which we used a novel implantation technique to reduce primary graft dysfunction. MATERIALS AND METHODS: We compared our experience with the novel method detailed in our article (Glasgow experience group) with a contemporary UK cohort (2015-2016) of patients (control group). We performed multivariable logistic regression to compare the Glasgow experience with the control group with primary graft dysfunction as the outcome measure. We adjusted for donor age, recipient diabetes mellitus, urgent listing status, bypass time, and total ischemic time. RESULTS: Among 194 patients in both cohorts, 140 patients (72.1%) were men and 36 (18.6%) had ischemic cardiomyopathy. The odds ratio of primary graft dysfunction in the control group was 2.99 (95% CI, 1.02- 8.75) compared with the Glasgow experience group. CONCLUSIONS: Our novel approach was associated with significant reductions in primary graft dysfunction, with a trend toward improved 1-year survival. Larger studies are needed to show differences after further adjustment for known confounders of primary graft dysfunction. We believe this novel technique is safe, cost-effective, and reproducible.

The effect of patient-prosthesis mismatch on survival after aortic and mitral valve replacement: a 10 year, single institution experience.

BACKGROUND: The evidence on the impact of patient-prosthesis Mismatch (PPM) on survival thus far has been conflicting. The aim of this study was to 1) study the effect of PPM on survival after isolated aortic and mitral valve replacement and 2) Assess the interaction between left ventricular function and PPM on survival. METHODS: The study cohort was patients who underwent isolated Aortic valve replacement (AVR) and Mitral valve replacement (MVR) over a 10-year period from 2008 to 2018. PPM was defined using the projected indexed effective orifice area (EOAi). The cohort was divided into different groups based on the degree of PPM. The severity of PPM was classified using threshold values of EOAi used in the literature. The Kaplan- Meier method was used to compare survival by degree of PPM. Multivariate Cox proportional hazards models were used to generate adjusted hazard ratios (HR) with 95% confidence intervals. An interactive term for ejection fraction (EF) was added to test whether EF modifies the effect of the PPM grade on survival. In addition, sub-group analysis based on left ventricular function was performed. RESULTS: In the AVR cohort, there were a total of 1953 patients. The distribution of patients in the different PPM categories was as follows: no PPM 59.7%; moderate PPM 36.8%; severe PPM 3.5%. There was no significant difference in survival between the different groups. At 10 years, the adjusted HR between patients with severe PPM versus no PPM was 1.1(CI 0.5-2.4, p >  0.05) and the HR between those with moderate PPM versus no PPM was 0.97 (CI 0.74-1.23, p >  0.05). In the MVR cohort, there were a total of 298 patients. The distribution of PPM is as follows: no PPM 59.4%; and with PPM 40.6%. Again, there was no significant difference in survival between the groups. At 5 years, the adjusted HR between patients with PPM versus no PPM was 1.45 (CI 0.67-3.14, p >  0.05). In both groups, there was no significant interaction between left ventricular function (LVF) and degree of PPM on survival. CONCLUSIONS: In our study cohort, the degree of PPM was not an independent predictor of survival after AVR or MVR. There was also no significant interaction between LV function and degree of PPM on survival.

Is it safe not to drain the pneumonectomy space?

A best evidence topic in thoracic surgery was written according to a structured protocol. The question addressed was whether it is safe not to position any chest drain into the pneumonectomy space at the conclusion of the procedure. Altogether 381 relevant studies were identified of which 11 represented the best evidence to answer the question. The author, journal, date, country of publication, alternative methods of postpneumonectomy space (PPS) management, complications and relevant outcomes are tabulated. The majority of studies are on the basis of expert opinion or small cohorts. Major cohorts, by which the pneumonectomy outcomes have been examined, demonstrated that the rates of complications related to pneumonectomy space management such as empyema, bronchopleural fistula, mediastinal shift and major bleeding requiring reopening are very low. In a large cohort where 408 patients underwent pneumonectomy the rate of relevant complications was low and also it was concluded that the PPS drainage is not necessary. Two separate expert opinions were in agreement that needle aspiration in the absence of a drainage system is adequate for the management of PPS and avoiding a mediastinal shift. One small cohort and one institutional audit directly examined the impact of a drainage versus no drainage approach in the management of PPS. Although neither study could show a significant superiority of one method over another, they recommended adopting a unified institutional protocol for current departmental practice. They also emphasized that larger cohorts are required to examine the superiority of different strategies for PPS management. In a cohort of 291 patients, it was demonstrated that patients with drainage with underwater seal are more at risk of postpneumonectomy oedema. A recent review published as a book chapter appraised the relevant literature in both humans and animals. The authors concluded that the simplicity of a no-drainage system is notable; however, a balanced drainage might be recommended for local protocols. We conclude that although the current evidence is not adequate to examine the different aforementioned approaches, not draining the pneumonectomy space can be performed safely.

A novel application of cerebral oximetry in cardiac surgery.

We report a novel use of cerebral oximetry in cardiac surgery using the Fore-Sight absolute cerebral oximeter (CAS Medical Systems Inc, Branford, CT). A patient with a persistent left superior vena cava underwent mitral and aortic valve replacement. We decided to tape and occlude the persistent left superior vena cava and used cerebral oximetry to compare left and right hemispheric oxygen saturation levels to ensure that cerebral perfusion was not impaired. The procedure was uneventful, and the patient was extubated 8 hours later without neurocognitive deficit.