Comparison of radiocephalic fistulas placed in the proximal forearm and in the wrist.

Non-maturation is a common problem in patients receiving an arteriovenous fistula. The first vascular access choice is a distal radiocephalic fistula (dRCF) at the wrist. Patients with a failed dRCF or with vessels unsuitable for dRCF, the recommendation is to place a brachiocephalic fistula in the upper arm. Proximal forearm radiocephalic fistulas (pRCF) are created infrequently, but may permit a second forearm fistula before proceeding to the upper arm. The goal of the present study was to compare the outcomes of them. We retrospectively analyzed a computerized access database to compare the outcomes of 19 RCF and 39 dRCF placed during a 6-month period. The baseline characteristics were similar, except those with a pRCF were more likely to have previous access and be male. Primary failure (non-maturation) was lower for pRCF than dRCF (32 vs. 59%, p = 0.05); and excluding secondary failures, cumulative fistula survival was similar (92 vs. 86% at 1 year and 74 vs. 76% at 2 years, p = 0.56). pRCF may be an attractive alternative to a brachiocephalic fistula in patients who cannot receive a dRCF. pRCF has a lower non-maturation rate than that of a dRCF, and a comparable cumulative survival once it is used successfully for dialysis.

Increased ventricular premature contraction frequency during rem sleep in patients with coronary artery disease and obstructive sleep apnea.

BACKGROUND: Patients with obstructive sleep apnea are reported to have a peak of sudden cardiac death at night, in contrast to patients without apnea whose peak is in the morning. We hypothesized that ventricular premature contraction (VPC) frequency would correlate with measures of apnea and sympathetic activity. METHODS: Electrocardiograms from a sleep study of 125 patients with coronary artery disease were evaluated. Patients were categorized by apnea-hypopnea index (AHI) into Moderate (AHI <15) or Severe (AHI>15) apnea groups. Sleep stages studied were Wake, S1, S2, S34, and rapid eye movement (REM). Parameters of a potent autonomically-based risk predictor for sudden cardiac death called heart rate turbulence were calculated. RESULTS: There were 74 Moderate and 51 Severe obstructive sleep apnea patients. VPC frequency was affected significantly by sleep stage (Wake, S2 and REM, F=5.8, p<.005) and by AHI (F=8.7, p<.005). In Severe apnea patients, VPC frequency was higher in REM than in Wake (p=.011). In contrast, patients with Moderate apnea had fewer VPCs and exhibited no sleep stage dependence (p=.19). Oxygen desaturation duration per apnea episode correlated positively with AHI (r(2)=.71, p<.0001), and was longer in REM than in non-REM (p<.0001). The heart rate turbulence parameter TS correlated negatively with oxygen desaturation duration in REM (r(2)=.06, p=.014). CONCLUSIONS: Higher VPC frequency coupled with higher sympathetic activity caused by longer apnea episodes in REM sleep may be one reason for increased nocturnal death in apneic patients.