Yasuhiro Hoshino

Negative pressure wound therapy for left ventricular assist device-related mediastinitis: two case reports

We report two cases of successful use of negative pressure wound therapy (NPWT) to control of left ventricular assist device (LVAD)-related mediastinitis. It is difficult to treat mediastinitis in patients who have undergone LVAD implantation, because it is impossible to remove the infected artificial materials from the mediastinal space. This report indicates that NPWT might become the preferred therapeutic option for control of mediastinitis in patients who have undergone LVAD implantation.

Successful management of apical abscess after Nipro left ventricular assisted device explantation by removal of apical cuff and omentopexy

Nipro-Toyobo-paracorporeal pulsatile flow VAD (Nipro VAD; Nipro, Osaka, Japan) has been used most commonly as a paracorporeal VAD (p-VAD) in Japan. There are few reports describing clinical course of post LVAD explantation and its complication. We herein present two cases of apical abscess after the explantation of the device. SSI is a main risk factor of formation of the apical abscess at the time of LVAD explantation. It is mandatory to perform sufficient debridement and closure of the layers including abdominal muscle and anterior abdominal fascia at exit sites in the explantation surgery. Omentopexy is also helpful for prevention from infection. Routine removal of apical cuff and outflow graft could be considered as one of the options when LVAD is explanted as bridge to recovery.

Does Body Size Matter for Continuous-Flow Ventricular Assist Device Implantation for Bridge to Transplantation?

Introduction With advancement of continuous flow ventricular assist device (Cf-VAD) technology, implantation and longer support has been becoming safer and safer. Miniaturization has also allowed us to implant cf-VAD in patients with small body size. There is still some concern about stable and safe support in patients with small body size. We sought to analyze our cf-VAD implantations for bridge to transplantation (BTT) to see if there was any difference in survival or complication rates by the body size. Material and Methods We analyzed 148 consecutive cf-VAD implantations for BTT (age: 39.7 years, 41 females) in our hospital. Ratio of female patients was significantly higher in group S (76%) than the other 2 groups (M: 24%, L: 0%). Devices used were HeartMate II in 55, Jarvik 2000 in 43, EVAHEART in 28, DuraHeart in 21 and HVAD in 1. Jarvik 2000 was more frequently used in group S (56%). There was no biventricular VAD requirement in this group. We divided patients into 3 groups according to body surface area (BSA); group S with < 1.5m2, group M with 1.5 to < 1.7m2 and group L with more than 1.7m2. BSA in each group was 1.39m2, 1.60m2 and 1.80m2 for groups S, M and L, respectively. Survival after cf-VAD implantation, pump exchange (due to pocket infection) free survival, pump exchange (due to pump thrombosis) free survival and pump exchange (due to infection or pump thrombosis) free survival were analyzed using Kaplan-Meier estimates with log-rank method for statistical analyses. Follow-up was censored at heart transplantation (HTx) or device explant due to functional recovery. Follow-up was 100% complete. Results and Discussion There was no difference in duration of support (627 days in S, 654 days in M and 686 days in L) and post-implantation follow-up period (33.0 months in S, 28.1 months in M and 36.3 months in L). Forty-three patients underwent HTx, 6 weaned from cf-VAD due to functional recovery and 14 required device exchange due to pump thrombosis or pocket infection. There was no difference in 1, 2 and 3 year survival after cf-VAD implantation (91.7%, 88.3 %, 84.6% in group L, 91.2%, 88.6%, 88.6% in group M and 91.5%, 87.6%, 87.6% in group S). No significant differences were observed in pump exchange (due to pocket infection) free survival, pump exchange (due to pump thrombosis) free survival and pump exchange (due to infection or pump thrombosis) free survival. Pump exchange free survival at 1, 2, 3 year was: 89.7%, 84.1%, 77.3% in group L, 87.7%, 85.2%, 55.1% in group M and 91.5%, 80.1%, 74.8% in group S. Conclusion Contemporary cf-VADs for BTT were safely implanted and managed up to 3 years in small size patients when an adequate device was chosen according to patient body size. Continued study on emerging devices in the future is mandatory to extrapolate the findings in this study to other centers and countries.

Novel driveline route for prevention from driveline infection: Triple tunnel method

BACKGROUND The most prevalent and serious infection related to left ventricular assist devices (LVADs) is driveline infection (DLI). From 2014, we employed a revised surgical technique (triple tunnel method), which deployed a longer subfascial driveline (DL) route. METHODS AND PATIENTS We retrospectively analyzed 34 patients fitted with either of the two types of axial pumps: HeartMate II (n=23) and Jarvik 2000 (n=11). Prior to 2014, the DL proceeded from the pump pocket just above the posterior sheath of the rectus muscle toward a vertical skin incision at the right lateral border of the rectus muscle. Then, DL was turned leftward into the subcutaneous tissue to redirect its exit to the left side [subcutaneous tissue group (Group S): n=14]. From 2014, we made an additional skin incision below the umbilicus with the aim of lengthening the subfascial DL route [muscle group (Group M): n=20]. RESULTS DLI occurred in 10 patients (71.4%) in Group S and in 1 patient (5%) in Group M (p<0.05, Chi-square test). The freedom rate from re-admission at 1 year due to DLI was 64% in Group S and 95% in Group M, respectively (p=0.021, log-rank test). Furthermore, logistic regression analysis revealed that DL route was significantly associated with DLI (odds ratio, 10.1; 95% confidence interval, 1.15-275.3). CONCLUSION Although a longer follow-up period will be needed, the triple tunnel method may be beneficial in the prevention of DLI.

Single-center experience of the bridge-to-bridge strategy using the Nipro paracorporeal ventricular assist device

Currently, we use the Nipro paracorporeal VAD (p-VAD) for initial short-term ventricular support, as a bridge to decision (BTD) or a bridge to candidacy (BTC) treatment, in Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) levels 1 and 2 patients. However, it is possible that compared to patients with primary implantable-VADs (P-iVAD), the bridge-to-bridge (BTB) patients are more likely to develop complications. This retrospective study used data from 24 consecutive BTB patients who were initially implanted with Nipro p-VAD as BTD or BTC treatments between April 2011 and March 2016, and subsequently underwent conversion to an i-VAD. The data from 72 patients who underwent a primary i-VAD (P-iVAD) procedure were used for comparison. Between the two groups, there was no significant difference in the incidence of infectious events (p = 0.72) or stroke (p = 0.44). Orthotropic heart transplantation was performed in 6 of the 24 patients in the BTB group and in 21 of the 72 patients in the P-iVAD group. The 1- and 2-year survival rates were 95.8% and 95.8% in the BTB group and 91% and 85.8% in the P-iVAD group; these values were not significantly different between groups (p = 0.91). Based on these results we conclude that BTB using Nipro p-VAD is a reasonable strategy for treating patients with severe decompensated end-stage heart failure.

The Incidence, Risk Factors, and Outcomes of Hyperlactatemia after Heart Transplantation: One Center's Experience

Hyperlactatemia (HL) is associated with tissue hypoperfusion during cardiac surgery, which results in postoperative morbidity and mortality among patients undergoing cardiopulmonary bypass surgery. The aim of this study was to determine the incidence, risk factors, and outcome of HL after heart transplantation (HTx) in one of the largest Japanese single-center cohorts. We retrospectively studied the lactate levels in 49 patients who underwent HTx at the University of Tokyo Hospital from August 1, 2010 to November 30, 2015. All of the patients were over 20 years of age. Arterial blood samples were analyzed during the operation and until 24 hours after surgery. Twenty-nine patients (59.2%) had HL after intensive-care unit admission. At 24 hours after surgery, the lactate levels of all patients had recovered to the normal range. A multivariate analysis showed that the total ischemic time of the donor heart (odds ratio [OR], 1.0176; 95% confidence interval [CI], 1.0004-1.0375; P = 0.0444) and the duration of preoperative left ventricular assist device (LVAD) support (OR, 0.9977; 95% CI, 0.9952-0.9997; P = 0.0218) were risk factors for HL. Pulmonary complications were noted in 24.1% of the patients with high lactate values but in none of the patients without HL (P = 0.0182); however, there were no cases of hospital death, and the length of hospital stay did not differ to a statistically significant degree between HL groups (P = 0.719). Although HL after HTx was common, it appeared to be transient and benign. Donor heart ischemia and the duration of preoperative LVAD support were associated with HL after transplantation.