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Biomedical subjects

P W Brady

Publications and source records attributed to P W Brady.

12 recordsLinked to original sources
PubMed2004

Bronchopulmonary sequestration supplied by the coronary circulation associated with a right-sided aortic arch.

Bronchopulmonary sequestration is an uncommon congenital anomaly. Although systemic arterial supply to the abnormal lung tissue is usually derived from the aorta, other nutrient vascular sources have also been described, including, infrequently, the coronary circulation. A right-sided aortic arch is another rare vascular abnormality, generally present in the setting of a vascular ring. We report a case of pulmonary sequestration receiving arterial supply from the right coronary artery, in the presence of a right-sided aortic arch, a constellation of anomalies not previously described.

Journal Article↗
PubMed2000

The heart string: a simple, inexpensive exposure of the heart during coronary artery operations.

A method of heart retraction during coronary artery bypass operations is described. The technique improves exposure of the coronary arteries, especially of the circumflex and posterior descending coronary branches during grafting. In addition, it is simple, safe, and inexpensive. Furthermore, this technique can be applied for off-pump coronary artery bypass surgery.

Cardiac Catheterization↗
PubMed2000

Ventricular remodeling after cardiomyoplasty in heart failure sheep: passive and dynamic effects.

BACKGROUND: Recent reports claim that cardiomyoplasty (CMP) has a girdling effect on the left ventricle, to prevent dilatation and functional deterioration, but the mechanism of its long-term effects on the native heart is not known. We compared the relative role of CMP's active squeezing and passive girdling in chronically failing hearts. METHODS: After induction of stable heart failure (left ventricular ejection fraction = 27% +/- 7%) by staged coronary microembolization, CMP was performed in 11 of 18 sheep. After 8 weeks pacing training of the latissimus dorsi muscle (LDM), cardiac assist was begun with 1:2 synchronous bursts in 6 sheep (d-CMP, n = 6), and the LDM in the passive group (p-CMP, n = 5) remained unstimulated. Four (base line) and 30 weeks after induction of heart failure, the pressure-volume relationship was derived. RESULTS: After 30 weeks in d-CMP the slope (Emax) of the end-systolic pressure-volume relationship increased by 66% +/- 55% (p < 0.05) and external work efficiency by 48% +/- 41% (p < 0.01). In the passive CMP and control groups, slope and external work efficiency were unchanged. Conversely, left ventricular end-diastolic volume decreased (-14% +/- 12%, p < 0.05) in the dynamic CMP group compared with a static course in the passive CMP group (3% +/- 10%, p > 0.05) and an increase (18% +/- 15%, p < 0.05) in controls. CONCLUSIONS: Dynamic CMP improved native heart's contractility and external work efficiency. In addition, whereas passive CMP has simply a girdling effect, dynamic CMP also induces reverse left ventricular chamber remodeling.

Animals↗
PubMed1998

Improved efficiency of energy transfer to external work in chronic cardiomyoplasty based on the pressure-volume relationship.

OBJECTIVE: Cardiomyoplasty is a surgical procedure to support the failing heart, in which a burst-stimulated latissimus dorsi muscle flap is transposed and wrapped around the ventricles. The effect of dynamic cardiac compression, implemented as cardiomyoplasty, on left ventricular performance remains controversial; the mechanism by which clinical symptoms are improved remains unclear. To investigate the mechanism for improvement of patients' symptoms, it is important to evaluate the effects of cardiomyoplasty on left ventricular energetics and on left ventricular systolic and diastolic function. We therefore evaluated the efficiency of energy transfer from the native pressure-volume area to external work under conditions of 1:3 skeletal muscle burst pacing in an animal model with chronic heart failure. METHODS: In seven Merino-Wether sheep, cardiomyoplasty was performed after stable heart failure was induced by staged coronary embolizations (ejection fraction < 35%). Hemodynamic assessment including the assessment of the pressure-volume relationship was performed 8 weeks after cardiomyoplasty when the latissimus dorsi muscle was fully trained. Instantaneous left ventricular pressure and volume were measured with a catheter-tipped manometer and a conductance catheter during steady-state conditions and after a transient inferior vena cava occlusion. The effect of dynamic cardiac compression on left ventricular systolic function was assessed by comparing pre-assisted and assisted beats and on diastolic function by comparing assisted and post-assisted beats. RESULT: The slope of the end-systolic pressure-volume relationship decreased by 30.5% +/- 27.8% (p = 0.02) during assisted beats. However, left ventricular pump performance improved by increasing stroke volume and external work by 35.9% +/- 36.0% (p = 0.03) and 9.7% +/- 6.8% (p = 0.03), respectively, resulting in a reduction of the volume intercept. As a result, the end-systolic pressure-volume relationship shifted to the left. The efficiency of energy transfer from the native pressure-volume area to the overall external work improved by 7.6% +/- 8.2% (p = 0.04). Cardiomyoplasty did not affect the time constant of left ventricular isovolumic pressure decline or the maximal rate of pressure decay, which suggested that cardiomyoplasty did not affect left ventricular relaxation. CONCLUSIONS: Dynamic cardiac compression in the form of cardiomyoplasty enhanced left ventricular pump performance without interrupting left ventricular filling. The ratio of energy transfer from the native pressure-volume area to the overall external work suggests a myocardial oxygen-sparing effect of cardiomyoplasty.

Animals↗
PubMed1993

Intra-aortic balloon rupture causing femoral entrapment.

Rupture of an intra-aortic balloon counterpulsator (IABCP) demands immediate removal. We report a case of thrombus formation within a Datascope IABCP secondary to IABCP rupture, necessitating surgical exploration for removal. There is a disturbing pattern of balloon ruptures with this type of IABCP.

Aged↗
PubMed1992

Complications from intra-aortic balloon counterpulsation: a review of 303 cardiac surgical patients.

From January 1980 to January 1990 all patients undergoing cardiac surgery at the Royal North Shore Hospital, Sydney, and requiring intra-aortic balloon counterpulsation (IABCP) were retrospectively reviewed. A total of 99 patients (32.6%) developed complications. Vascular/haemorrhagic complications occurred in 46 patients (15.2%); 79 patients (26%) required platelet transfusions. We have found that only a history of hypertension was predictive of an increased incidence of developing vascular complications. Surgical intervention was required in 17 patients (5.6%), or 47% of the patients who developed a vascular complication. The mortality among patients requiring IABCP was 36.6%. Intra-aortic balloon pump-related deaths occurred in 6 patients (2%). Use of the intra-aortic balloon pump can be a life-saving procedure, but it carries a significant morbidity and mortality rate. This makes it imperative to temper our indications to those patients who demonstrate a need for it.

Adult↗
PubMed1992

Technical improvements in the repair of acute postinfarction ventricular septal rupture.

Postinfarction ventricular septal rupture (VSR) is a high-risk complication following myocardial infarction (MI). Surgical treatment has evolved to improve an otherwise poor prognosis. Certain subsets of patients remain a formidable challenge. The presence of cardiogenic shock has consistently been found to have the highest risk. Over a 10-year period, our technique of repair has evolved from established procedures to one we believe confers superior results. Endocardial patching to viable myocardium reinforced with an epicardial patch not only corrects the shunt but maintains ventricular geometry and avoids tension on friable muscle. We report on a series of nine consecutive patients in cardiogenic shock. The operative mortality was 22%, none due to low cardiac output syndrome, shunt recurrence, or bleeding. All patients have been followed with transesophageal echocardiography at a mean period of 14 months (range 3-31 months). One patient is in New York Heart Association (NYHA) Class I, four are in NYHA Class II, and two in NYHA Class III.

Aged↗
PubMed1988

An unusual cause of mitral incompetence: post-traumatic paraprosthetic mitral incompetence.

Nonpenetrating chest trauma, particularly that involving high-speed, may cause a variety of cardiac and aortic injuries. Cardiac valvular disruption following trauma is uncommon. Two cases of paraprosthetic mitral incompetence following blunt chest trauma are presented to document this entity and to discuss its investigation and management. Clinical examination and a high index of suspicion are foremost in making the diagnosis. Noninvasive tests may not confirm clinical diagnosis and cardiac catheterization has provided confirmation of clinical diagnosis.

Aged↗
PubMed1987

Results of a technique of mitral valve repair.

A particular technique for mitral repair of the posterior leaflet prolapse of the mitral valve has been used at Royal North Shore Hospital over a 15-year period. The anatomical details, complications and results of repair, as well as mortality, are reviewed in a group of 49 patients. Surgery in this group was performed with three peri-operative deaths. Three patients required re-operation due to the failure of repair; one patient within one month of surgery and the others at 6.5 and 9 years. All patients improved symptomatically following mitral repair. This series demonstrates that the repair of posterior leaflet prolapse can be performed in all patient age groups with low mortality and morbidity rates. A low incidence of reoperation for failure of repair and other complications related to valve surgery can be anticipated.

Adult↗
PubMedDate not supplied

Adverse reactions to plasma volume expanders.

Plasma volume expanders are effective in the restoration of blood volume. All the available plasma volume expanders may rarely induce anaphylactoid reactions, although such reactions are extremely uncommon in shocked patients. The reactions are caused by different mechanisms depending on the solution, and there is little evidence that IgE antibodies are involved. In addition to these reactions, effects on haemostasis and renal function may occur, and the persistence of hydroxyethyl starch in the body has led to concern about its potential role as a carcinogen, although there is no evidence to suggest that this has occurred.

Animals↗