David S. Feldman

BACKGROUND: Patients with advanced heart failure have improved survival rates and quality of life when treated with implanted pulsatile-flow left ventricular assist devices as compared with medical therapy. New continuous-flow devices are smaller and may be more durable than the pulsatile-flow devices. METHODS: In this randomized trial, we enrolled patients with advanced heart failure who were ineligible for transplantation, in a 2:1 ratio, to undergo implantation of a continuous-flow device (134 patients) or the currently approved pulsatile-flow device (66 patients). The primary composite end point was, at 2 years, survival free from disabling stroke and reoperation to repair or replace the device. Secondary end points included survival, frequency of adverse events, the quality of life, and functional capacity. RESULTS: Preoperative characteristics were similar in the two treatment groups, with a median age of 64 years (range, 26 to 81), a mean left ventricular ejection fraction of 17%, and nearly 80% of patients receiving intravenous inotropic agents. The primary composite end point was achieved in more patients with continuous-flow devices than with pulsatile-flow devices (62 of 134 [46%] vs. 7 of 66 [11%]; P<0.001; hazard ratio, 0.38; 95% confidence interval, 0.27 to 0.54; P<0.001), and patients with continuous-flow devices had superior actuarial survival rates at 2 years (58% vs. 24%, P=0.008). Adverse events and device replacements were less frequent in patients with the continuous-flow device. The quality of life and functional capacity improved significantly in both groups. CONCLUSIONS: Treatment with a continuous-flow left ventricular assist device in patients with advanced heart failure significantly improved the probability of survival free from stroke and device failure at 2 years as compared with a pulsatile device. Both devices significantly improved the quality of life and functional capacity. (ClinicalTrials.gov number, NCT00121485.)

We performed a retrospective analysis of thirty-three consecutive total hip and knee (twenty-three hip and ten knee) revision arthroplasties during which intraoperative frozen sections were analyzed. Data for the study were collected by means of a review of the charts, radiographic analysis, and evaluation of both frozen and permanent histological sections. The frozen sections, of periprosthetic tissue at the bone-cement interface or the pseudocapsule, were considered positive for active infection if there were more than five polymorphonuclear leukocytes per high-power field in at least five distinct microscopic fields. All patients were available for follow-up, at an average of thirty-six months (range, seventeen to seventy-nine months) after the initial revision operation. The frozen sections from ten patients were positive for infection, and those from twenty-three patients were negative. Comparison of the results of the analyses of the frozen sections (both positive and negative) with those of the analyses of the permanent histological sections of similar tissue showed a correlation of 100 per cent (sensitivity, 1.00; specificity, 1.00; and accuracy, 1.00). Nine patients had positive intraoperative cultures, and all of them had positive frozen sections (sensitivity, 1.00). Of the twenty-four patients who had negative intraoperative cultures, twenty-three had negative frozen sections (specificity, 0.96). Of the nine patients who had positive intraoperative cultures, only two were found to have infection on intraoperative gram-staining. The surgeon's operative assessment regarding the presence of infection, compared with the final pathological diagnosis, demonstrated a sensitivity of 0.70, a specificity of 0.87, and an accuracy of 0.82. All ten patients who had positive frozen sections were managed with excision arthroplasty; six of them subsequently had reimplantation, and the excision was the definitive procedure in the remaining four. One patient who had had a delayed reimplantation had a secondary skin slough and eventually was managed with an arthrodesis of the knee. In the group that had negative frozen sections, eighteen patients had a primary exchange revision arthroplasty and five had a delayed reimplantation. At the time of follow-up, one patient who had had a delayed reimplantation had radiographic loosening of the femoral component and was asymptomatic. One patient who had had a primary exchange arthroplasty was managed with a second revision because of aseptic loosening. There was no clinical recurrence of infection in any patient. The data indicate that analysis of frozen sections of periprosthetic tissue is a reliable predictor of the presence of active infection during revision joint arthroplasty. We recommend its use to differentiate aseptic from septic loosening.