Surgical outcomes after cardiac surgery in liver transplant recipients.

OBJECTIVE: This was a single-center retrospective study to assess the surgical outcomes and predictors of mortality of liver transplant recipients undergoing cardiac surgery. METHODS: From 2000 to 2010, 61 patients with a functioning liver allograft underwent cardiac surgery. The mean interval between liver transplantation and cardiac surgery was 5.4 ± 4.4 years. Of the 61 patients, 33 (54%) were in Child-Pugh class A and 28 in class B. The preoperative and postoperative data were reviewed. RESULTS: The overall in-hospital mortality was 6.6%. The survival rate was 82.4% ± 5.1% at 1 year and 50.2% ± 8.2% at 5 years. Cox regression analysis identified preoperative encephalopathy (odds ratio, 5.2; 95% confidence interval, 1.8-15.5; P = .003) and pulmonary hypertension (odds ratio, 3.5; 95% confidence interval, 1.3-9.4; P = .045) as independent predictors of late mortality. The preoperative Model for End-Stage Liver Disease (MELD) scores of patients who died in-hospital or late postoperatively were significantly greater statistically than the scores of the others (in-hospital death, 23.7 ± 7.8 vs 13.1 ± 4.5, P < .001; late death, 15.2 ± 6.1 vs 12.3 ± 4.1, P = .038). The Youden index identified an optimal MELD score cutoff value of 13.5 (sensitivity, 56.0%; specificity, 67.6%). Kaplan-Meier survival analysis successfully demonstrated that the survival rate of the MELD score less than 13.5 (MELD <13.5) group was significantly greater than that of the MELD >13.5 group (MELD <13.5 group, 93.8% ± 4.2% at 1 year and 52.4% ± 11.8% at 5 years; MELD >13.5 group, 66.9% ± 9.6% at 1 year and 46.1% ± 11.1% at 5 years; P = .027). In contrast, the survival rate when stratified by Child-Pugh class (class A vs B) was not significantly different. CONCLUSIONS: Cardiac surgery in the liver allograft recipients was associated with acceptable surgical outcomes. Preoperative encephalopathy and pulmonary hypertension were independent predictors of late mortality. The cutoff value of 13.5 in the MELD score might be useful for predicting surgical mortality in cardiac surgery.

Percutaneous subxiphoid access to the epicardium using a miniature crawling robotic device.

BACKGROUND: : To expand minimally invasive beating-heart surgery, we have developed a miniature 2-footed crawling robot (HeartLander) that navigates on the epicardium. This paradigm obviates mechanical stabilization and lung deflation, and avoids the access limitations of current approaches. We tested the locomotion of the device on a beating porcine heart accessed through a closed-chest subxiphoid approach. METHODS: : HeartLander consists of 2 modules that are connected by an extensible midsection. It adheres to the epicardium using suction pads. Locomotion and turning are accomplished by moving the 2 modules in an alternating fashion using wires that run through the midsection between them. After a preliminary test with a plastic beating-heart model, we performed a porcine study in vivo. The device was inserted into the pericardial space through a subxiphoid incision, while the test was observed using a left thoracoscopy. The blood pressure and electrocardiogram were monitored, and vacuum pressure and driving forces on the wires were recorded. RESULTS: : HeartLander traveled across the anterior and lateral surfaces of the beating heart without restriction, including locomotion forward, backward, and turning. The vacuum pressure was kept below 450 mm Hg at all times. The average maximum force during elongation was 1.86 ± 0.97 N, and during retraction was 1.24 ± 0.33 N. No adverse hemodynamic or electrophysiologic events were noted during the trial. No epicardial damage was found on the excised heart after the porcine trial. CONCLUSIONS: : The current HeartLander prototype demonstrated safe and successful locomotion on a beating porcine heart through a closed-chest subxiphoid approach.