Pulmonary atresia with intact ventricular septum

Neonates with pulmonary atresia with intact ventricular septum are ductus dependent from birth. The initial approach in these patients is to ensure continued adequate pulmonary blood flow in anticipation of imminent spontaneous closure of the ductus. Our experience and evolving approach in the management of 16 consecutive neonates with pulmonary atresia with intact ventricular septum from 1978 to 1984 is presented. On the basis of the revised classification by Bull and associates, we divided the patients into four different groups according to right ventricular morphology. Basically, three types of palliative surgical procedures were performed: systemic-pulmonary artery shunt; systemic-pulmonary artery shunt with pulmonary valvotomy; and pulmonary valvotomy alone. Systemic-pulmonary artery shunt is the most important part of neonatal palliation. Our present routine is to perform left subclavian-main pulmonary artery shunt with a polytetrafluoroethylene tube in all patients and, in addition, to perform an open transpulmonary valvotomy without cardiopulmonary bypass in patients with a patent infundibular portion of the right ventricle. Our technique and the advantages of this type of shunt procedure are discussed. Patients with right ventricular sinusoidal-coronary artery communications are a subgroup with an additional problem. In our series, patients with this anomaly are categorized into groups with major and minor connections and their surgical significance is discussed. Overall, there was one death among 16 patients after neonatal palliative procedures and one death among five patients after hemodynamic repair.     

FEASIBILITY OF CONDUCTING CARDIOVASCULAR OUTCOME RESEARCH IN AUSTRALIAN GENERAL PRACTICE: RESULTS FROM THE ANBP2 PILOT STUDY

1. The present study aimed to determine the feasibility of conducting a 5 year cardiovascular outcome trial of the treatment of 6000 elderly hypertensive patients in Australian general practices. 2. General practitioners (GPs) were invited to participate by mail and personal follow-up. Patient records were reviewed to identify subjects for a blood pressure (BP) screening programme. Blood pressure was measured on three occasions and eligible subjects were included if the average BP was 160 mmHg systolic or 90 mmHg diastolic if systolic BP was 140 mmHg. 3. Seven hundred and forty-one GPs were approached and 89 were enrolled in the study (12% of mail invites and 75% of those receiving a personal contact). In 16 practices where screening was completed, 82 000 records were reviewed to identify 4% patients eligible for screening. Twenty-two per cent of eligible subjects attended screening. Of 1938 subjects screened, 180 (9%) had BP 5=160/90 mmHg. Forty-seven percent of subjects (n = 916) were receiving antihypertensive therapy and 184 (20%) were withdrawn from therapy. One hundred and sixteen (63%) of these subjects had BP return to study entry levels within 6 weeks. Fifty-seven newly diagnosed and 81 previously treated subjects were randomized (7% of the screened population). 4. Based on the high participation rate of GPs, the response rate of patients to attend a BP screening programme and the 7% randomization to screening ratio for entry into the study, the ANBP2 pilot study has demonstrated that it is feasible to recruit subjects from Australian general practices to a cardiovascular outcome trial.     

Early results for anatomic correction of transposition of the great arteries and for double-outlet right ventricle with subpulmonary ventricular septal defect

Fifty patients, 21 with transposition of the great arteries plus ventricular septal defect, four with double-outlet right ventricle plus ventricular septal defect, and 25 with transposition of the great arteries plus intact ventricular septum, have undergone anatomic correction. There were four hospital deaths, all in the patients with ventricular septal defects (overall mortality rate 8%). The Lecompte maneuver was used in all patients, and in the last 25 patients the coronary arteries were transposed to medially hinged trapdoor flaps created in the neoaorta. In 10 patients (20%) intraoperative adjustments were necessary to the great vessels and coronary arteries to achieve unobstructed coronary artery flow. There have been no late deaths. Postoperative cardiac catheterization in 19 patients has revealed stenosis on the new main pulmonary artery suture line to be the main early problem. Anatomic correction of transposition (with or without ventricular septal defect) and double-outlet right ventricle septal defect would seem to be a good operative alternative to the Mustard or Senning operation, with the advantage of incorporating the left ventricle into the systemic circulation.     

Cardiac conduction abnormalities and rhythm changes after neonatal anatomical correction of transposition of the great arteries.

Seventy three infants who underwent neonatal anatomical correction for transposition of the great arteries with or without a ventricular septal defect were reviewed for evidence of conduction and rhythm abnormalities on preoperative and postoperative 12 lead electrocardiograms and during 24 hour Holter monitoring. There was a partial right bundle branch block pattern in 47% (29/62) of all patients and in 60% (24/40) of those with simple transposition. Complete right bundle branch block was noted in 21% including 5% with simple transposition. Holter monitoring showed sinus rhythm in all patients except three: one had episodes of supraventricular tachycardia, another an intermittent second degree heart block, and a third a complete heart block. Atrial extrasystoles were noted in 47% (29/62) of patients but were frequent in only three patients. Occasional unifocal ventricular extrasystoles were encountered in 37% (23/62) of patients and were frequent in a further 3% (2/62). Only one patient (2%) developed multifocal ventricular extrasystoles. The frequency of important cardiac arrhythmias after neonatal anatomical correction of transposition of the great arteries was 5%, significantly less than that reported after atrial inflow diversion for the same malformation.     

Urea rebound and delivered Kt/V determination with a continuous urea sensor

BACKGROUND: The recent introduction of urea sensors for dialysis monitoring has made possible new approaches to urea kinetic modelling. In this study we show how the equilibrated postdialysis urea concentration (Ceq) and Kt/V corrected for double-pool urea kinetics (Kt/Vdp) can be accurately determined using an on-line sensor providing a continuous measure of blood water urea. A modification of the Smye constant volume double-pool theory led to the following equations for Ceq and Kt/Vdp [formula: see text] where Cpre is the blood concentration measured at the start of dialysis, t is the length of the dialysis session (in min) and S(ex) is the constant slope of the blood urea logarithm concentration decline following development of the intercompartmental urea concentration gradient in the first 30-60 min of dialysis. METHODS: These equations were tested in 11 patients undergoing 165-240 min of paired filtration dialysis with continuous monitoring of blood urea concentration. Cpre was determined as the plateau concentration during a preliminary period of 15-20 min of slow isolated ultrafiltration. S(ex) was accurately determined from linear regression applied to the urea sensor data from the 80-min point to the end of dialysis. RESULTS: Ceq and Kt/Vdp determined from the above equations compared closely to values determined from 25-40 min of urea rebound monitoring with the urea sensor: 10.6 +/- 3.0 versus 10.8 +/- 2.7 mmol/l (mean +/- SD) for Ceq and 1.21 +/- 0.24 versus 1.18 +/- 0.20 for Kt/Vdp, compared to single-pool values of Kt/V = 1.34 +/- 0.23. CONCLUSION: This technique may be readily programmed into on-line urea monitors to provide current and extrapolated values of Ceq and Kt/Vdp from about the first hour of dialysis.      

Small interfering RNA inhibits SARS-CoV nucleocapsid gene expression in cultured cells and mouse muscles

SARS-CoV isa newly identified coronavirus that causes severe acute respiratory syndrome （SARS）. Currently, there is no effective method available for prophylaxis and treatment of SARS-CoVinfections. In the present study, the influence of small interfering RNA （siRNA） on SARS-CoV nucleocapsid （N） protein expression was detected in cultured cells and mouse muscles. Four siRNA expression cassettes driven by mouse U6 promoter targeting SARS-CoV N gene were prepared, and their inhibitory effects on expression of N and enhanced green fluorescence protein （EGFP） fusion protein were observed.