Citations

Abstract Introduction Doxorubicin is an anthracycline used as a chemotherapeutic drug for the treatment of a wide range of adult and pediatric cancers. Doxorubicin is associated with an increased risk of cardiomyopathy and heart failure with up to 10% of patients developing cardiac complications. A GWAS conducted of 1,191 patients from the N9831 clinical trial identified that cardiac gene expression and genetic variants of TRPC6 were associated with a decline in left ventricular ejection fraction (LVEF) (p=0.005 and p=1.6x10–6, respectively). TRPC6 is a non-selective cation channel expressed in heart and vascular tissue. TRPC6 participates in the pathogenesis of cardiac hypertrophy as a pathological response to chronic mechanical stress. Chronic activation has been found to promote cardiac fibrosis leading to heart failure. Purpose TRPC6 variants could be associated with increased risk of doxorubicin-induced cardiotoxicity. Data/tests to determine which patients may progress to cardiomyopathy and heart failure are currently lacking and there are no targeted treatments to prevent cardiomyopathy in these patients. Methods In preliminary in vivo data, B6.129 wild-type mice or TRPC6 knockout mice were treated with either 6x intraperitoneal saline or 4mg/kg doxorubicin injections (cumulative dose of 24mg/kg). Results We found doxorubicin increased cardiac vacuolation (male, p≤0.001 and female, p≤0.05) in WT mice compared to controls. Higher HW/BW ratio was observed in male TRPC6 knock out mice compared to wild-type mice when both were treated with doxorubicin (males, p=0.005 and females, p=0.19). Additionally, we found that doxorubicin-induced cardiac injury was significantly reduced in TRPC6 knock-out mice compared to wild-type mice based on reduced vacuolation (p=0.0004 males, p=0.03 females), with the effect being greater in male mice than female mice. Furthermore, a significant decrease in stroke volume (p=0.007), diastolic volume (p=0.01) and cardiac output (p=0.004) in wild-type male mice treated with doxorubicin compared to control and TRPC6 knock-out mice. Our in vitro preliminary data show that inhibition of TRPC6 using the TRPC6 inhibitor GsMTx-4 in human iPSC-derived cardiomyocytes significantly reduced doxorubicin-induced apoptosis (p<0.0001). Further we treated male mice with the TRPC6 inhibitor, GsMTx4, and found that they had less global longitudinal cardiac strain (p=0.04) and higher ejection fraction (p=0.01) compared to mice who were only treated with doxorubicin. Histologically we found that mice given the TRPC6 inhibitor had less fibrosis as measured by Trichrome stained heart sections (p=0.004) which could account for improvements in cardiac function. Conclusion TRPC6 could be a novel therapeutic target in the prevention of chemotherapy-induced cardiomyopathy and heart failure. Additionally genetic mapping of TRCP6 functional variants may provide a new screening tool to determine increased risk of developing heart failure. Funding Acknowledgement Type of funding sources: Private hospital(s). Main funding source(s): Mayo Clinic

Background: Immunocompromised (IC) patients are at greater risk from cardiac surgery. Transcatheter aortic valve replacement (TAVR) may be more preferable for treating severe aortic stenosis (AS), though data regarding outcomes of IC patients are limited. Methods: We reviewed TAVR procedures performed at our institution from 1/2015-12/2019.We defined IC as either active malignancy receiving oncologic treatment or post organ transplant on immunosuppression, HIV, chronic steroid use (>5mg/day), or autoimmune disorder. Survival probability was estimated using the Kaplan-Meier (KM) method. Cox regression was used to evaluate the association of IC with survival. Results: Of 173 patients who underwent TAVR, 56 (32%) were IC: 30 (54%) had active malignancy undergoing active treatment, 19 (34%) were IC without malignancy, and 7 (13%) had both. Among the 19 IC patients without malignancy, 4 were post organ transplant, 3 were taking chronic steroids, 2 had autoimmune disorder, 1 had HIV, and 10 had ≥2 combination of the above. IC patients, as compared to non-IC patients, had similar baseline demographics and STS risk score (median 4.3 vs. 4.4), respectively. There were 37 deaths (16 IC and 21 non-IC) over a median follow up of 1.4 years (IQR 1.0-2.0 years). 1-year survival after TAVR was 84.5% for IC patients and 89.0% for non-IC patients (log rank p = 0.51). After adjusting for age and sex, an association between IC and survival was observed but not found to be statistically significant (adjusted HR, 1.55; 95% CI, 0.80-3.00). Conclusions: IC patients undergoing TAVR have similar baseline characteristics as non-IC patients with a trend towards worse survival. Longer term follow-up may help clarify the impact of IC status on survival after TAVR.

A 53-year-old male patient was presented to our institution with the clinical picture of biventricular failure. The echocardiogram revealed congenitally corrected transposition of the great arteries, dextrocardia with situs solitus, atrioventricular discordance and ventriculoatrial discordance, severe systemic and mitral valves regurgitation, and severe pulmonary hypertension (mean pulmonary artery pressure: 51 mm Hg). He underwent heart–lung transplant. He was discharged on postoperative day 25 with left ventricular ejection fraction of 60%–65%, and with oxygen independency.

The use of extracorporeal circulation (ECC) for intraoperative cardiopulmonary support during lung transplantation has been increasing in the recent years. Our group previously described a novel hybrid extracorporeal membrane oxygenation (ECMO) circuit for use in lung transplantation. Our novel technique for intraoperative management of this circuit during lung transplantation is described.

Background and aim of the study: Congenitally corrected transposition of the great arteries (cc-TGA) is a rare type of congenital heart disease and heart-lung transplant (HLTx) is the potential solution if the patient developed severe biventricular failure.. Aim of the study is to present a challenging case of cc-TGA with dextrocardia managed by HLTx. Methods: A 53-year-old male patient was presented to our institution with biventricular failure. The echocardiogram revealed cc-TGA, dextrocardia with situs solitus, atrioventricular discordance and ventriculoatrial discordance, severe systemic and sub-pulmonary atrioventricular valves regurgitation, and severe pulmonary hypertension. He underwent heart-lung transplant. Results: The patient was discharged on postoperative day 25 on room air with normal left ventricular ejection fraction. Conclusion: This case highlights the complexity of preoperative and intraoperative management of cc-TGA, and demonstrates the challenges which the surgeons and anesthesiologists may face during the procedure of HLTx.

Extracorporeal circulation (ECC) support using intraoperative extracorporeal membrane oxygenation (ECMO) during lung transplantation (LTx) is now a routine practice for many high volume centers. Circuits that are dedicated to ECMO alone can be expensive and do not allow full cardiopulmonary bypass (CPB) to be performed. We describe our technique of instituting venoarterial ECMO during LTx using a less-expensive hybrid circuit that facilitates easy and immediate conversion to full CPB if needed, without interruption of ECC.