Potential renal protective benefits of intra-operative BNP infusion during cardiac transplantation.

BACKGROUND: Recombinant BNP (nesiritide) is known to reduce endothelin levels, cause afferent arteriole vasodilation, and increase natriuresis and diuresis. We hypothesized that intraoperative infusion of BNP may benefit renal function in cardiac transplant patients. METHODS: From June 2003 to September 2005, 22 consecutive heart transplant patients received BNP at a dose of 0.01 microg/kg/min before initiation of cardiopulmonary bypass (group A). BNP infusion was continued for a mean of 3.3 +/- 1.9 days. Hemodynamics, urine output, and serum creatinine levels were prospectively collected and compared with 22 consecutive patients who underwent heart transplantation between May 2002 and June 2003 following the identical transplant protocol, but without BNP infusion (group B). RESULTS: At 24 hours postoperatively, mean blood pressure was comparable between groups (87 +/- 11 mm Hg vs 89 +/- 17 mm Hg, P = .7), but pulmonary artery pressure (18 +/- 5 mm Hg vs 24 +/- 5 mm Hg, P = .001) and central venous pressure (12 +/- 5 mm Hg vs 16 +/- 4 mm Hg, P = .01) were lower with BNP infusion, whereas cardiac index was augmented (2.8 +/- 0.5 vs 2.4 +/- 0.6, P = .03). Requirement of low-dose inotropic and vasopressor support was equally distributed between groups (P > or = .72). Postoperative urine output for the initial 24 hours was higher in group A (84 +/- 15 vs 55 +/- 36 mL/h, P = .01). None of the patients with BNP infusion required additional diuretics or renal replacement therapy during the first week after transplantation. Mean postoperative serum creatinine levels as compared with preoperative values remained unchanged within group A (P = .12), but increased significantly in group B (P < .001). CONCLUSIONS: Intraoperative BNP infusion in heart transplant recipients was associated with favorable postoperative hemodynamics, significantly improved urine output, and stable serum creatinine levels. A prospective, randomized, multicenter trial is warranted to evaluate the potential renal protective benefits of intraoperative BNP infusion in this patient population.

Surgical treatment of atrial fibrillation with bipolar radiofrequency ablation: mid-term results in one hundred consecutive patients.

AIM: The Cox-Maze procedure was introduced nearly two decades ago for the surgical treatment of atrial fibrillation (AF). Recently, our group has replaced most of the incisions of the Cox-Maze procedure with bipolar radiofrequency (RF) ablations (Cox-Maze IV procedure). The purpose of this study was to examine our midterm results with the Cox-Maze procedure using bipolar RF ablation. METHODS: From January 2002 to October 2005, 100 consecutive patients underwent a modified Cox-Maze procedure with bipolar RF ablation for AF; 32 were lone operations, and 68 were concomitant procedures. Follow-up was performed at 1, 3, 6, and 12 months, and then annually thereafter. Heart rhythm was confirmed by electrocardiography. RESULTS: The mean age of patients was 62+/-13 years; 57% were male. Duration of AF was 6.3+/-7.6 years (0.1 to 40 years), 59% had paroxysmal AF, and 34% had permanent AF. Follow-up was complete for all patients with a mean follow-up of 13+/-10 months. At 12-month follow-up, 91% (49/54) of patients were free of AF. Cross-clamp time in the lone Cox-Maze IV procedure patients was 42+/-15 minutes, while it was 101+/-29 minutes for the Cox-Maze IV with a concomitant procedure (compared to 93+/-34 minutes and 122+/-37 minutes for the traditional procedure, P<0.05). There were four operative deaths. CONCLUSIONS: The Cox-Maze IV procedure had good mid-term efficacy. The use of bipolar RF energy significantly decreased operative time and simplified the procedure compared to the traditional Cox-Maze procedure, potentially increasing utilization of the procedure among cardiac surgeons.

Acquisition of oral phencyclidine self-administration in rhesus monkeys: effect of sex.

RATIONALE: There are increasing reports of sex differences in the etiology of drug abuse in humans. A nonhuman primate model is useful for examining sex as a variable in drug abuse. OBJECTIVES: To determine whether there are sex differences in the acquisition of oral phencyclidine (PCP) self-administration and to compare the effect of altered feeding conditions on drug self-administration in male and female monkeys. METHODS: Acquisition of orally delivered PCP was studied using 7 female and 11 male adult rhesus monkeys. Initially, the monkeys were not food restricted, and they were given access to water under concurrent fixed-ratio (FR) 1 schedules during daily 3-h sessions. Each lip-contact response on a drinking spout resulted in a 0.3 ml liquid delivery. After baseline levels of water intake were obtained for 5 days, water was replaced with PCP (0.125 mg/ml) at both drinking spouts. Body weights were then reduced to 85% of free-feeding weights, and the monkeys were fed 30 min before the session began. The FR value was increased from 1 to 2, 4, and 8, at both drinking spouts. As a final step in the procedure, water and PCP were concurrently available at the two spouts under FR 8 schedules. Acquisition of PCP-reinforced behavior was considered to have occurred if PCP intake was consistently greater than water intake. RESULTS: Lip-contact responses and liquid deliveries were not significantly different between the females and males throughout the acquisition period, but there was a significant increase in responding and decrease in liquid intake as FR increased, and a significant increase in PCP consumption due to food restriction that did not differ in males and females. On a milligram per kilogram basis, female monkeys consumed nearly twice as much PCP as the males; however, this effect was not significant. The females showed significantly higher PCP than water intake while the males consumed approximately equal amounts of PCP and water. Of the seven females, 100% met the acquisition criterion of significantly greater PCP than water intake, while only 36.4% of the males met the criterion. CONCLUSION: These results concur with previous rat studies and indicate that female monkeys are more likely than males to acquire drug-reinforced behavior.