Quantitative Indices of Intra-Aortic Balloon Pump (IABP) Dependence During Post-Infarction Cardiogenic Shock

In an attempt to quantitate intra-aortic balloon pump (IABP) dependence and differentiate retrievable post-infarction cardiogenic shock situations, thirty-five patients were analyzed in regard to age, duration of IABP support, and hemodynamic performance. Survivors were younger than non-survivors (P<0.01) and the duration of IABP support in survivors was greater than that of non-survivors (P<0.05). When duration of IABP support was plotted against age, three zones of increasing dependence and mortality were apparent. In Zone 1 (ages 32–40), there was no dependence or mortality; in Zone 2 (ages 40–65, IABP durations < 250 hours), there were several instances of dependence and a 63% mortality; in Zone 3 (ages gt; 65 or IABP durations > 250 hours), there was a 100% mortality. IABP dependence was best recognized by time-course trajectory plots of cardiac index versus systemic vascular resistance. Three trends were observed. All patients who improved to Class A (CIgt; 2.1 L/min/m², SVR< 2100 dynes sec cm^-5) survived unless they succumbed to sudden ventricular dysrhythmias. Patients who remained in Class B (1.2 L/min/m² < CI< 2.1 L/min/m², with SVR's < 2100 dynes sec cm^-5) for 7–14 days were IABP-dependent and eventually expired. Patients who deteriorated to or remained in Class C (CI< 1.2 L/min/m² or SVR> 2100 dynes sec cm^-5) expired early despite IABP support and were considered irretrievable. This study suggests that post-infarction cardiogenic shock IABP-dependence can be quantitated to a certain degree. Post-infarction IABP-dependent patients are relatively young (40–55), do not expire during the first 50 hours of IABP support, neither improve nor deteriorate during the second 50 hours of support, and remain in Class B for 7–10 days without the occurrence of life-threatening ventricular dysrhythmias. In such situations, sufficient time may be available for cardiac catheterization to determine the appropriateness of subsequent operative interventions.     

Molecular, Microscopic, Microstructural and Mechanical Methods of Analyzing Pseudoneointimal Linings within Partial Artificial Hearts in Man and the Calf

Ex vivo molecular, microscopic (cellular), microstructural and mechanical methods have been utilized to evaluate biologic, blood-interfacing linings (pseudneointima) formed on textured, fibril-flocked pumping surfaces within abdominal left ventricular assist devices (ALVADs) or partial artificial hearts. Thus far, seventeen human and twenty bovine pseudoneointimal linings (1–28 day pumping durations) have been evaluated by these methods. The results indicate that pseudoneointima begins developing within 24 hours after contact of the pumping surface with blood and is well developed at five days. The linings exhibit surface immunofluorescent fibrinogen activity, viable surface macrophages and histiocytes and scattered erythrocytes at ALVAD removal. Structurally similar linings (20 μ to 500 μ in thickness) develop in calves and in man. Mechanically, pseudoneointima is a stable, adherent, highly compliant, isotropic structural material. It is linearly elastic and strain-rate independent, with small viscous energy losses under physiologic strains. The methods employed for the evaluation of pseudoneointima provide useful information to determine the suitability of textured or rough surfaces for blood interfacing. The cumulative results indicate that the textured surface approach is useful for intermediate-term clinical ALVAD utilization.     

An Abdominal Left Ventricular Assist Device: Preclinical Studies

An abdominally positioned left ventricular assist device (ALVAD) has been evaluated in our most recent series of 25 calves weighing 99 ± 12 kg. The ALVAD is a pneumatically actuated bladder pump, positioned subdiaphragmatically and connected between the left ventricular apex and the infrarenal abdominal aorta. The mean survival time in the calves was 41 days and the longest 65 days. The major effects of the pump are reductions of all indices of left ventricular work and increases in systemic perfusion. In the awake, unanesthetized calf, left ventricular pressure, dP/dt, and stroke work were decreased while peak aortic pressure, stroke volume, and cardiac output increased. These effects were corroborated at cardiac catheterization two to four weeks postoperatively; left ventriculograms also showed increases in ejection fraction. These data demonstrate the ALVAD's effectiveness in assuming left ventricular function and support over extended periods. The device has been developed for short-term postoperative clinical use in patients with reversible left ventricular failure.     

Development and Evaluation of a Long-Term, Implantable, Electrically Actuated Left Ventricular Assist System: THI/Gould LVAS

Summary: A long-term, impĺantable, electrically actuated left ventricular assist system (THI/Gould LVAS) is being developed and characterized in vitro and in vivo for utilization in patients with end-stage heart disease. This system consists of five major components: a long-term, implantable blood pump (THI E-type ALVAD); an electrical-mechanical energy converter (Gould Model V); a control unit with batteries; a volume compensation system; and an external power supply and monitoring unit. Two of these components (blood pump and electrical-mechanical energy converter) have been integrated, and are undergoing chronic in vivo evaluations in calves. Thus far, 44 pneumatically and electrically actuated THI/Gould LVAS evaluations have been performed. This experience has resulted in >6.5 years of actuation in vivo , with durations exceeding 1 year. System in vivo performance in terms of durability, mechanical reliability, hemodynamic effectiveness, and biocompatibility has been satisfactory. Demonstration of long-term (2-year) effectiveness in supporting the circulation is the ultimate goal.     

Subacute toxicity and recovery tests of mequitazine in beagle dogs (author's transl)

Subacute toxicity and recovery tests of Mequitazine, a new phenothiazine ;type anti-histamine agent, were carried out using each 20 male and female dogs. The drugs was administered orally in doses of 0, 1, 5 and 25 mg/kg day for 14 weeks. Recovery test was carried out for following 4 weeks. As a result, transient decrease of the body weights and somnolences were observed in both male and female dogs given 25 mg/kg. In a female dog given 25 mg/kg, extrapyramidal reaction accompanied with tremors and muscle stiffenings was observed. But no dead animals were observed throughout experimental period. Vomitings, mydriasis and loss of appetite were observed with the dose-responsiveness, but these symptoms were reduced after 1-2 weeks administration. No abnormal changes were observed in hematological, serum biochemical, and other examinations. In histopathological examinations, slights changes were observed in liver, kidneys, mesenteric lymph nodes, palpebra and conjunctival membrane. But these changes were reversible in recovery period. From these results, it was suggested that the maximum non-effective and maximum safety doses were 1 mg/kg/day and 5 mg/kg/day, respectively.     

How do parents of 4‐ to 5‐year‐old children perceive the weight of their children?

Introduction: A heavier weight in adults is becoming the norm rather than an abnormal weight. Whether the same trend is happening in children is unknown. Objective: To assess the perception of the weight of 4‐ to 5‐year‐old children and the recognition of overweight by both parents. Design: Population‐based survey. Participants: A questionnaire was sent to parents of 1155 4‐ to 5‐year‐old children. Results: In total, 439 questionnaires (35%) were returned. Of all, 90% of the children had a normal weight, 9.3% were overweight and 4.1% were obese. For all weight classes, the parents depicted the child as lighter on both the verbal and visual scale. Of all, 75% of mothers of overweight children stated that the child had a normal weight. In obese children, 50% of the mothers believed that the child had a normal weight. Conclusion: Children with a weight in the normal range were considered by their parents as a little too light or too light. Overweight was considered as normal weight, and obesity as normal or a little too heavy. The perception of a normal weight in children at 4–5 years is distorted.     

Ten-year NEDO BVAD development program: moving forward to the clinical arena

Since 1995, the Baylor Group has been developing a totally implantable NEDO BVAD system. This 10-year program was completed in March 2005, and preparation for clinical trials is underway. This article summarizes the entire 10-year NEDO program and describes the strategy for clinical trials. The project aimed to achieve: (1) dual centrifugal pumps with the ability of full biventricular support, (2) a compact system implantable into small adults, (3) a totally implantable system with transcutaneous energy transmission system (TETS), (4) a durable system with a lifetime of over 5 years, and (5) a system free of thrombus and with minimal hemolysis. The final goals are to complete preclinical system evaluations and commence the clinical trials in the near future. In vitro studies have demonstrated a pump capacity of over 8.5 l/min and an Index of Hemolysis of <0.004 g/100 l. The pump-bearing life expectancy was over 5 years. To date, eight pumps endured in vivo studies of over 3 months without complications, including thromboembolic events. The in vitro endurance studies of eight pumps are longer than 1 year. There were no mechanical malfunctions or pump failure. A stepwise clinical trial is being planned: Step1, a wearable BVAD/VAD will be clinically studied; Step 2, the BVAD/VAD will be implanted intracorporeally without TETS; and, Step 3, a totally implantable system will be clinically evaluated. The NEDO BVAD system has completed preclinical testing. Clinical trial preparation is underway.     

Fatigue Intervention by Nurses Evaluation – The FINE Trial. A randomised controlled trial of nurse led self-help treatment for patients in primary care with chronic fatigue syndrome: study protocol. [ISRCTN74156610]

Background

A major change has occurred in the last few years in the therapeutic approach to patients presenting with all forms of acute coronary syndromes. Whether or not these patients present initially to tertiary cardiac care centers, they are now routinely referred for early coronary angiography and increasingly undergo percutaneous revascularization. This practice is driven primarily by the angiographic image and technical feasibility. Concomitantly, there has been a decline in expectant or ischemia-guided medical management based on specific clinical presentation, response to initial treatment, and results of noninvasive stratification. This 'tertiarization' of acute coronary care has been fuelled by the increasing sophistication of the cardiac armamentarium, the peer-reviewed publication of clinical studies purporting to show the superiority of invasive cardiac interventions, and predominantly supporting (non-peer-reviewed) editorials, newsletters, and opinion pieces.

Discussion

This review presents another perspective, based on a critical reexamination of the evidence. The topics addressed are: reperfusion treatment of ST-elevation myocardial infarction; the indications for invasive intervention following thrombolysis; the role of invasive management in non-ST-elevation myocardial infarction and unstable angina; and cost-effectiveness and real world considerations. A few cases encountered in recent practice in community and tertiary hospitals are presented for illustrative purposes The numerous and far-reaching scientific, economic, and philosophical implications that are a consequence of this marked change in clinical practice as well as healthcare, decisional and conflict of interest issues are explored.

Summary

The weight of evidence does not support the contemporary unfocused broad use of invasive interventional procedures across the spectrum of acute coronary clinical presentations. Excessive and unselective recourse to these procedures has deleterious implications for the organization of cardiac health care and undesirable economic, scientific and intellectual consequences. It is suggested that there is need for a new equilibrium based on more refined clinical risk stratification in the treatment of patients who present with acute coronary syndromes.