Biomedical subjects

Andrew Boyle

Publications and source records attributed to Andrew Boyle.

7 recordsLinked to original sources

PubMed2026

Initial 4-Year Experience With Microaxial Flow Pumps Within a Tertiary Centre in Regional Australia.

BACKGROUND & AIM: The Microaxial Flow Pump (MFP) is a miniaturised rotary pump that aspirates blood from the left ventricle and expels it into the ascending aorta. It unloads the left ventricle and increases mean arterial pressure and cardiac output. MFP is most commonly utilised in cardiogenic shock, for protected percutaneous coronary intervention (PCI), and for ventricular offloading in veno-arterial extracorporeal membrane oxygenation (VA-ECMO). METHOD: We conducted a retrospective review of all patients who underwent MFP insertion at John Hunter Hospital, Australia. Categorical data are represented as counts and percentages, with continuous variables described as means with standard deviations. RESULTS: Twenty-three MFP devices were inserted between September 2020 and May 2024. Five (22%) were for protected PCI, three (13%) for venting with VA-ECMO (ECPELLA), and 15 (65%) for acute coronary syndrome (ACS) and cardiogenic shock. The median age for the overall cohort was 62 years, with a 74% male predominance. Eighty percent of the protected PCI cohort were elective outpatient procedures, and there were no deaths in this cohort. The mortality in the ECPELLA group was 67%. Thirteen (87%) of the patients with cardiogenic shock presented with an anterior infarct, and 53% had cardiac arrest on admission. The overall morality in the cardiogenic shock cohort was 40%. Complications in this cohort included limb ischaemia in four patients (17%) and site bleeding in seven patients (30%). Four patients (17%) required vascular surgery intervention. CONCLUSION: Our initial experience showed the use of MFP in a tertiary centre was safe and feasible, allowing progression from protected percutaneous intervention to acute cardiogenic shock.

Humans↗

PubMed2006

Redefining the therapeutic objective in decompensated heart failure: hemoconcentration as a surrogate for plasma refill rate.

BACKGROUND: Acute decompensated heart failure is a growing epidemiologic problem about which little consensus exists on guidelines and recommendations for therapy. METHODS AND RESULTS: Available databases suggest that a large percentage of patients are being inadequately decongested while hospitalized, resulting in poor clinical outcomes. This is partly from a lack of an appropriate target to define therapeutic success. The demonstration of a prerenal state by blood work does not indicate adequate decongestion but rather means that the rate of fluid removal has exceeded the plasma refill rate. Hemoconcentration, as evidenced by a rising hematocrit is an appropriate surrogate to indicate that the plasma refill rate has been exceeded by the rate of fluid removal. This surrogate of plasma refill rate can be easily and continuously measured by using an in-line hematocrit sensor during ultrafiltration therapy. CONCLUSION: We propose that the therapeutic objective in acute decompensated heart failure should be redefined and that the rate of volume extraction should be adjusted to approximate the plasma refill rate and that complete decongestion will have occurred only once hemoconcentration is observed at minimal rates of volume extraction.

Body Weight↗

PubMed2005

Ultrafiltration versus usual care for hospitalized patients with heart failure: the Relief for Acutely Fluid-Overloaded Patients With Decompensated Congestive Heart Failure (RAPID-CHF) trial.

OBJECTIVES: The purpose of this research was to assess the safety and efficacy of ultrafiltration (UF) in patients admitted with decompensated congestive heart failure (CHF). BACKGROUND: Ultrafiltration for CHF is usually reserved for patients with renal failure or those unresponsive to pharmacologic management. We performed a randomized trial of UF versus usual medical care using a simple UF device that does not require special monitoring or central intravenous access. METHODS: Patients admitted for CHF with evidence of volume overload were randomized to a single, 8 h UF session in addition to usual care or usual care alone. The primary end point was weight loss 24 h after the time of enrollment. RESULTS: Forty patients were enrolled (20 UF, 20 usual care). Ultrafiltration was successful in 18 of the 20 patients in the UF group. Fluid removal after 24 h was 4,650 ml and 2,838 ml in the UF and usual care groups, respectively (p = 0.001). Weight loss after 24 h, the primary end point, was 2.5 kg and 1.86 kg in the UF and usual care groups, respectively (p = 0.240). Patients tolerated UF well. CONCLUSIONS: The early application of UF for patients with CHF was feasible, well-tolerated, and resulted in significant weight loss and fluid removal. A larger trial is underway to determine the relative efficacy of UF versus standard care in acute decompensated heart failure.

Adrenergic beta-Antagonists↗

PubMed2005

Ultrafiltration for acute decompensated heart failure.

For the 13th consecutive year, acute decompensated heart failure is the most common reason for admission to American hospitals. Most patients admitted for decompensated heart failure are by definition, diuretic resistant. The therapeutic objective in these patients is volume and sodium removal, and the restoration of diuretic sensitivity. In a significant proportion of patients, this objective is not met, subjecting patients to readmission for recurrent (or continued) heart failure decompensation. Ultrafiltration therapy offers the potential of greater volume and sodium removal as compared with conventional therapies in a more expeditious manner. Ultrafiltration can be accomplished safely, quickly and on a regular telemetry ward in extremely ill patients, but relies on earlier discharge with reduced readmission rates to be economically feasible.

Acute Disease↗

PubMed2004

Down-regulation of plasminogen activator inhibitor 1 expression promotes myocardial neovascularization by bone marrow progenitors.

Human adult bone marrow-derived endothelial progenitors, or angioblasts, induce neovascularization of infarcted myocardium via mechanisms involving both cell surface urokinase-type plasminogen activator, and interactions between beta integrins and tissue vitronectin. Because each of these processes is regulated by plasminogen activator inhibitor (PAI)-1, we selectively down-regulated PAI-1 mRNA in the adult heart to examine the effects on postinfarct neovascularization and myocardial function. Sequence-specific catalytic DNA enzymes inhibited rat PAI-1 mRNA and protein expression in peri-infarct endothelium within 48 h of administration, and maintained down-regulation for at least 2 wk. PAI-1 inhibition enhanced vitronectin-dependent transendothelial migration of human bone marrow-derived CD34+ cells, and resulted in a striking augmentation of angioblast-dependent neovascularization. Development of large, thin-walled vessels at the peri-infarct region was accompanied by induction of proliferation and regeneration of endogenous cardiomyocytes and functional cardiac recovery. These results identify a causal relationship between elevated PAI-1 levels and poor outcome in patients with myocardial infarction through mechanisms that directly inhibit bone marrow-dependent neovascularization. Strategies that reduce myocardial PAI-1 expression appear capable of enhancing cardiac neovascularization, regeneration, and functional recovery after ischemic insult.

Adult↗

PubMed2004

Recipient selection and management.

Cardiac transplantation remains the definitive surgical solution for Stage D heart failure. However, the lack of availability of donor organs makes patient selection crucial to appropriate resource utilization. All feasible medical and surgical alternatives should be explored before consideration of transplantation is undertaken. A cardiac transplantation evaluation should be thorough to exclude patients with preexisting serious comorbidities, with particular attention being paid to renal dysfunction, pulmonary hypertension, and panel reactive antibody levels. Once accepted for listing as a cardiac transplantation recipient, patients are assigned a priority status based on the severity of illness. Organs are allocated on the basis on status level, blood type, body size, and length of time at a given status level.

Health Status Indicators↗

PubMed2003

Coronary artery stent thrombosis associated with exercise testing.

Chest pain following coronary artery stenting is common, yet finding the cause can be difficult. Exercise testing has long been used in the assessment of chest pain, but its usefulness in patients who have recently undergone coronary artery stenting is in doubt. A case of exercise testing appearing to precipitate acute stent thrombosis in a patient several weeks post-coronary artery stenting is reported and compared to a similar case in the literature. The role of exercise testing in the assessment of chest pain early after coronary artery stenting is then reviewed.

Journal Article↗