HeartWare and HeartMate II left ventricular assist devices as bridge to transplantation: a comparative analysis

BACKGROUND

The purpose of this study is to comparatively analyze outcomes of heart transplant patients bridged to transplantation with HeartWare (HW-VAD) versus HeartMate II (HMII-VAD) left ventricular assist devices.

METHODS

The United Network for Organ Sharing Database was reviewed to identify first-time heart transplant recipients who were bridged to transplantation with either HW-VAD (n=141) or HMII-VAD (n=1824) from January 2009 through July 2012.

RESULTS

Recipients of HW-VAD had a higher proportion of female patients (27.0% versus 18.9%; p=0.019), a lower body surface area (2.01±0.25 m2 versus 2.06±0.25 m2; p=0.035), and a trend toward a higher peak percentage of panel reactive antibody against human leukocyte class I antigens (40.4%±32.8% versus 33.0%±30.4%; p=0.070). Pretransplantation recipient cardiac index (2.33±0.66 L⋅min(-1)⋅m(-2) versus 2.33±0.68 L⋅min(-1)⋅m(-2)), serum creatinine (1.21±0.43 mg/dL versus 1.26±0.57 mg/dL), and total bilirubin (1.34±3.45 mg/dL versus 1.06±1.84 mg/dL) were comparable between the two groups (p>0.05 for all comparisons). After transplantation, there were no significant differences in freedom from rejection or freedom from cardiac allograft vasculopathy. Posttransplant graft survival rates were similar between the HW-VAD group and the HMII-VAD group at 1, 2, and 3 years (88.4% versus 87.8%, 79.9% versus 83.8%, and 77.4% versus 79.9%, respectively; p=0.843).

CONCLUSIONS

These findings suggest similar hemodynamic unloading, pretransplant end-organ function, and posttransplant outcomes in patients bridged to transplantation with both the HW-VAD and HMII-VAD.

Effects of differing heat and humidity on the performance and recovery from multiple high intensity, intermittent exercise bouts

The aim of this study was to determine the effects of different conditions of heat and humidity on two multiple bouts of high intensity cycling with 60 min recovery between each bout. Eight males (age: 25.5+/-1.8 yr, height: 179.0+/-3.7 cm; weight: 72.3+/-4.0 kg; VO2peak: 51.5+/-2.4 ml x kg(-1) x min(-1), Peak Aerobic Power: 366+/-13 W) volunteered for this study. After undertaking VO2peak testing, all participated randomly, in three consecutive 30 s Wingate tests in three different environmental conditions being: Normal (22 degrees C/30% RH), Wet (30 degrees C/85% RH), and Hot (40 degrees C/40% RH). Subjects were then monitored for the 60 min post-exercise period after which time they repeated the Wingate tests and were again monitored for 60 min. Blood samples were taken pre, immediately post exercise, and at 1, 5, 10, 15, 30, 45, and 60 min into each of the recovery periods and analysed for lactate, pH, and hematocrit. Heart rate was monitored continuously throughout exercise (5 s average) and recovery (60 s average). Weight was measured pre exercise and at 15, 30, 45, and 60 min post-exercise. Urine samples were collected at the same time and analysed for osmolality. The results of the experiment indicated that environmental conditions had no effect on the performance of either series 1 or 2 Wingate tests. Neither were there any changes in weight throughout the three conditions or across the condition. Post exercise pH levels were lower than pre exercise values (p < 0.0001) and the reverse was true for blood lactate levels (p < 0.0003). We conclude that anaerobic exercise is not unduly affected by hot or humid conditions when subjects can re-hydrate according to decreases in body weight.

Sequence and evolution of rhesus monkey alphoid DNA

Analysis of rhesus monkey alphoid DNA suggests that it arose by tandem duplication of an ancestral monomer unit followed by independent variation within two adjacent monomers (one becoming more divergent than the other) before their amplification as a dimer unit to produce tandem arrays. The rhesus monkey alphoid DNA is a tandemly repeated, 343-bp dimer; the consensus dimer is over 98% homologous to the alphoid dimers reported for baboon and bonnet monkey, 81% homologous to the African green monkey alpha monomer, and less than 70% homologous to the more divergent human alphoid DNAs. The consensus dimer consists of two wings (I and II, 172 and 171 bp, respectively) that are only 70% homologous to each other, but share seven regions of exact homology. These same regions are highly conserved among the consensus sequences of the other cercopithecid alphoid DNAs. The three alpha-protein binding sites reported for African green monkey alpha DNA by F. Strauss and A. Varshavsky (Cell 37: 889-901, 1984) occur in wings I and II, but with one site altered in wing I. Two cloned dimer segments are 98% homologous to the consensus, each containing 8 single-base-pair differences within the 343-bp segment. Surprisingly, 37% of these differences occur in regions that are evolutionarily conserved in the alphoid consensus sequences, including the alpha-protein binding sites. Sequence variation in this highly repetitive DNA family may produce unique nucleosomal architectures for different members of an alphoid array. These unique architectures may modulate the evolution of these repetitive DNAs and may produce unique centromeric characteristics in primate chromosomes.