Aortic dissection and triplets: treble the trouble.
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Adult↗
Biomedical subjects
J Pepper
Publications and source records attributed to J Pepper.
Interdisciplinary pilot project in a rehabilitation setting.
This project qualitatively evaluated the planning, implementation, and outcome of an interdisciplinary model of clinical education. Expectations of physiotherapy (PT), occupational therapy (OT), and speech-language pathology (SLP) students and clinicians were assessed to determine whether the model allowed for the acquisition of the interdisciplinary knowledge and skills needed for current practice. Students from OT (n = 5), PT (n = 3), and SLP (n = 1) undertook normally scheduled five-to-eight-week clinical placements, beginning on the same start date. All students were at intermediate or senior levels in their programs. Discipline-specific activities were supervised by clinical instructors from the disciplines. Interdisciplinary sessions during the first five weeks covered cross-disciplinary activities related to clinical reasoning, interviewing techniques, professionalism, and communication skills for team reporting. Themes related to the clinical experience were derived from student and supervisor responses to pre-and post-placement questionnaires, post-placement focus group interviews, and student journals. The response to the model was positive. The students felt they had gained insights into developing interdisciplinary skills, although they did feel that some discipline-specific needs were not met. The instructors were less enthusiastic but, given better planning and communication before the placement, welcomed the opportunity to try it again.
Canada↗
Will stentless valves be durable? The Toronto valve (TSPV) at 5 to 6 years.
The early hemodynamic benefits of stentless aortic valves have been well documented. The issue of long-term functional integrity remains unanswered. We report the clinical results of a multicenter registry with prospective data on 621 patients monitored for 7.1 years. Patient data were collected and analyzed at St Jude Medical Inc, St Paul, Minnesota. In all, 66% of patients were male; the average age was 65.9 years +/-11.0 years, with 39% older than 70 years. Native aortic valves were bicuspid in 40.6%, 91.5% were calcified and 65.7% stenotic. Most valves implanted (83.1%) were sizes 25, 27, or 29 mm. Concomitant coronary bypass was performed in 42% of patients. Total follow-up time for the 621 patients was 1,944.5 valve years (mean 3.1 years per patient). At 5 years, 86.1% (n = 137) and at 6 years 80.4% (n = 51) were in New York Heart Association class I, and 78% had no or trivial atrial insufficiency. The average mean systolic gradient for all valves at 6 years was 4.0 mm Hg, and the peak gradient was 8.6 mm Hg. The effective orifice area varied from 1.4 cm2 (23-mm valve) to 2.7 cm2 (29-mm valve). The decrease in left ventricular mass index was significant and sustained. Actuarial survival at 6 years was 84.2%, and freedom from cardiac-related deaths was 90.1%. Freedom from valve-related deaths was 95.7%, and freedom from prosthetic endocarditis was 98.6%. There were no instances of primary tissue valve failure during follow-up, with 97.2% freedom from reoperation. The early hemodynamic benefits of the TSPV are well maintained during more than 6 years of follow-up, without evident valvular dysfunction. Longer follow-up time is required to validate durability, but there is increasing evidence for well-maintained structural and functional integrity.
Actuarial Analysis↗
Hemodynamics and left ventricular mass regression following implantation of the Toronto SPV stentless porcine valve.
Stentless tissue valves may provide more favorable hemodynamics than conventional stented valves. Hemodynamic findings from a large multicenter trial have not been previously reported. The present report describes the hemodynamic findings from a multinational, multicenter study after implantation of the Toronto SPV valve. A total of 577 patients underwent aortic valve replacement with the Toronto SPV valve at 12 sites in 3 countries. Echocardiograms were recorded in the early postoperative period, 3 to 6 months after surgery, 1 year after surgery, and yearly thereafter, with follow-up to 3 years. Gradients decreased and effective orifice area increased in the months after surgery. One year after surgery, mean gradient for valve sizes 20 to 22, 23, 25, 27, and 29 mm was 7.3 +/- 4.4, 7.4 +/- 4.5, 6.1 +/- 3.3, 4.9 +/- 2.4, and 4.0 +/- 2.1 mm Hg, respectively; effective orifice area was 1.3 +/- 0.7, 1.5 +/- 0.5, 1.7 +/- 0.4, 2.0 +/- 0.4, and 2.4 +/- 0.6 cm2, respectively. There was a very low prevalence of significant aortic regurgitation at all time periods. There was significant left ventricular (LV) mass regression between the early and 3- to 6-month periods and between the 3- to 6-month and 1-year postoperative periods. The Toronto SPV valve has an excellent hemodynamic profile supported by significant regression of LV hypertrophy in the year after implantation. Data through 3 years demonstrates maintenance of low gradients and freedom from significant aortic regurgitation.
Aged↗
Comparison of 201Tl, 99mTc-tetrofosmin, and dobutamine magnetic resonance imaging for identifying hibernating myocardium.
BACKGROUND: Both radionuclide perfusion tracers and contractile response to dobutamine have been used to identify hibernating myocardium. The aim was to compare 201Tl (thallium) single photon emission CT (SPECT), 99mTc-tetrofosmin (tetrofosmin) SPECT, and dobutamine cine MRI for identifying regions of reversible myocardial dysfunction. METHODS AND RESULTS: Thirty patients with 3-vessel coronary artery disease and impaired left ventricular function (mean LVEF, 24.0%; SD, 8.3%) scheduled for coronary bypass grafting were recruited. All underwent rest/dobutamine stress (5 to 10 microg . kg-1 . min-1) cine MRI, stress/rest tetrofosmin SPECT, and stress/redistribution and separate-day rest/redistribution thallium SPECT before surgery. Stress/redistribution thallium SPECT and resting MRI were repeated after surgery. In a 9-segment model, SPECT images were scored visually for tracer uptake, which was also measured from a polar plot of myocardial counts. MRI was scored visually for endocardial motion, myocardial thickening, and thickness. Five patients died before follow-up, and 2 declined postoperative investigation. In the remaining 23 patients, mean LVEF increased from 24.0% (SD, 8.3%) to 29.7% (SD, 11.1%) (P<0.05). Of 207 segments analyzed, 145 had significantly abnormal wall motion before surgery, and 82 of these improved function after revascularization. The criteria for predicting recovery of severely hypokinetic segments on preoperative imaging were tracer uptake graded "moderately reduced" or better, or positive inotropic response on dobutamine MRI. Late-rest thallium images showed the highest sensitivity (76%), compared with stress-redistribution thallium (68%) and rest tetrofosmin (66%) (P<0.05). All 3 tracer techniques were nonspecific (44%, 51%, and 49%, respectively). Redistribution of thallium after the resting injection was insensitive (18%) but highly specific (83%). Inotropic response to dobutamine was also insensitive (50%) but specific (81%). CONCLUSIONS: Radionuclide uptake is a sensitive but nonspecific predictor of myocardial functional recovery, whereas dobutamine MRI is specific but insensitive.
Adult↗
Downregulation of immunodetectable connexin43 and decreased gap junction size in the pathogenesis of chronic hibernation in the human left ventricle.
BACKGROUND: The regional wall motion impairment and predisposition to arrhythmias in human ventricular hibernation may plausibly result from abnormal intercellular propagation of the depolarizing wave front. This study investigated the hypothesis that altered patterns of expression of connexin43, the principal gap junctional protein responsible for passive conduction of the cardiac action potential, contribute to the pathogenesis of hibernation. METHODS AND RESULTS: Patients with poor ventricular function and severe coronary artery disease underwent thallium scanning and MRI to predict regions of normally perfused, reversibly ischemic, or hibernating myocardium. Twenty-one patients went on to coronary artery bypass graft surgery, during which biopsies representative of each of the above classes were taken. Hibernation was confirmed by improvement in segmental wall motion at reassessment 6 months after surgery. Connexin43 was studied by quantitative immunoconfocal laser scanning microscopy and PC image software. Analysis of en face projection views of intercalated disks revealed a significant reduction in relative connexin43 content per unit area in reversibly ischemic (76.7+/-34.6%, P<.001) and hibernating (67.4+/-24.3%, P<.001) tissue compared with normal (100+/-30.3%); ANOVA P<.001. The hibernating regions were further characterized by loss of the larger gap junctions normally seen at the disk periphery, reflected by a significant reduction in mean junctional plaque size in the hibernating tissues (69.5+/-20.8%) compared with reversibly ischemic (87.4+/-31.2%, P=.012) and normal (100+/-31.5%, P<.001) segments; ANOVA P<.001. CONCLUSIONS: These results indicate progressive reduction and disruption of connexin43 gap junctions in reversible ischemia and hibernation. Abnormal impulse propagation resulting from such changes may contribute to the electromechanical dysfunction associated with hibernation.
Adult↗
The effect of angiotensin converting enzyme inhibition on myocardial function and blood pressure after coronary artery bypass surgery--a randomised study.
OBJECTIVE: To investigate the effect of 6 weeks' pre-operative treatment with the angiotensin converting enzyme inhibitor, quinapril, on left ventricular function when measured 3 months after coronary artery bypass graft surgery and to examine the safety of such treatment. PATIENTS AND METHODS: Patients (96) [86 males, 10 females; mean age 61 years] with chronic stable angina, on the waiting list for coronary artery bypass graft surgery, underwent measurement of left ventricular function by resting radionuclide ventriculography. Patients were then randomised to quinapril 20 mg once daily or placebo in a double-blind fashion, in addition to existing anti-anginal therapy and this regimen was continued for up to 6 weeks prior to operation. Measurement of left ventricular function was repeated 3 months following surgery, after recommencement of pre-surgery anti-anginal therapy for 1 week. Effects on systemic vascular resistance (SVR) during bypass were calculated from perfusion records and vasoconstrictor use during operation was documented. The safety of the addition of quinapril to the anti-anginal regimen was assessed by measurement of systemic blood pressure (BP) after the first dose of study medication, measurement of intra-operative BP, administration of inotropes and any intra-operative complications. RESULTS: There was no difference between treatment groups in the pre-study left ventricular ejection fraction (mean (S.D.); 54.9 (13.8)% versus 55.6 (13.2)%, quinapril versus placebo, respectively), or 3 months after surgery (58.1 (13.6)%, versus 56.9 (12.6)%, quinapril versus placebo, respectively). Left ventricular ejection fraction 3 months after surgery did not change significantly from pre-treatment in either group (2.8 (10.7)% and 1.5 (10.1)%; quinapril and placebo, respectively). There was no first-dose hypotension (systolic BP < 100 mmHg). The intra-operative BP and the SVR during bypass in the two treatment groups were not significantly different. The ischaemic time (mean = 56 min) and the use of inotropes were the same in both groups and there was no mortality. CONCLUSIONS: Angiotensin converting enzyme inhibitor treatment before coronary artery bypass graft surgery does not have a significant beneficial effect on left ventricular function following coronary artery bypass graft surgery. Angiotensin converting enzyme inhibition, administered in addition to anti-anginal therapy, does not cause first-dose hypotension or increase morbidity or mortality and can safely be used in patients with coronary heart disease prior to coronary artery bypass graft surgery.
Adult↗
Gastrointestinal permeability following cardiopulmonary bypass: a randomised study comparing the effects of dopamine and dopexamine.
OBJECTIVE: To compare the effects of dopexamine and dopamine on the mucosal permeability of the gastrointestinal tract (GIT). DESIGN: Prospective, randomised clinical trial. SETTING: Intensive care unit of a postgraduate teaching hospital, London, England. PATIENTS: Thirty patients undergoing elective surgery involving cardiopulmonary bypass, performed by a single surgeon. INTERVENTIONS: Patients were randomly assigned to receive either dopexamine 2.0 micrograms/kg per min or dopamine 2.5 micrograms/kg per min for the duration of the study period. MEASUREMENTS AND MAIN RESULTS: Hemodynamic parameters and gastric intramucosal pH (pHi) were measured at intervals throughout the study. GIT permeability was measured once, post-operatively, using the ratio of absorbed lactulose to L-rhamnose. The groups were similar with respect to demographics, pre- and post-operative risk factors. The lactulose/rhamnose ratio was (mean +/- SEM) 0.44 +/- 0.10 in the dopexamine group vs 0.65 +/- 0.08 in that receiving dopamine (p < 0.05). The dopexamine group had a significantly higher oxygen delivery preoperatively (479.5 +/- 32.0 ml/min per m2 vs 344.4 +/- 23.9 ml/min per m2 for dopamine, p < 0.01), but no other significant differences emerged between the groups. CONCLUSIONS: Compared to dopamine, dopexamine reduces GIT permeability following surgery involving cardiopulmonary bypass. The mechanism of this effect remains unclear.
APACHE↗
Phosphatidylcholine coated chest drains: are they better than conventional drains after open heart surgery?
INTRODUCTION: Inadequate thoracic drainage after open heart surgery has serious deleterious consequences. Thrombus formation within the chest drains is primarily responsible for the occlusion of chest drains. Chest drains coated with derivatives of phosphatidylcholine (PC), commonest phospholipid on cell membranes, potentially have a less thrombogenic surface. MATERIALS AND METHODS: In a prospective randomised double blind study, we compared PC-coated drains (Group I, n = 25) with non coated drains (Group II, n = 26) after open heart surgery. Drain performance, post-operative complications and clinical course were compared. RESULTS: PC-coated drains had a significantly shorter period of drainage, 20.4 +/- 1.0 versus 28.9 +/- 3.7 h (P < 0.05). Otherwise, mean volume drained, number clots removed from drain and the ease of drainage of the two types of drains were similar. There were no significant differences in the incidence of post-operative pericardial effusions, dysrhythmias, ambulation time and hospital stay. CONCLUSIONS: We conclude that the PC coated drains may be of importance in cases where prolonged drainage is anticipated otherwise they have no significant advantage.
Adult↗
Hibernating myocardium: clinical and functional response to revascularisation.
OBJECTIVE: We assessed the effects of coronary bypass grafting on left ventricular (LV) function, exercise capacity and symptom profile in patients with LV impairment and evaluated the role of identifying myocardial hibernation in a prospective non-randomised study. METHODS: Of 120 patients screened, 47 patients with LV ejection fraction < 35% and three vessel coronary artery disease were studied. All underwent stress/redistribution and separate day rest/redistribution T1-201 imaging together with cine MRI at enrolment, and cine MRI at follow-up. Group 1, 30 patients undergoing bypass surgery, underwent symptom limited treadmill exercise testing with peak VO2 measurement, and symptom profile evaluation less than 3 months before, and 3-6 months after operation. Revascularisation was assessed by post-operative T1-201 imaging and repeat coronary angiography. Group 2, 17 patients treated on medical therapy alone underwent symptom profile assessment at enrolment and follow-up for those who survived. Segmental hibernation was defined as the equivalent of greater than 50% of maximal T1-201 uptake where wall motion was severely impaired on resting imaging. Patients were considered to be hibernating where two of nine LV segments fulfilled these criteria. RESULTS: In group 1, five patients died (17%), peri-or post-operatively, two defaulted and 23 attended follow-up studies. In group 2, three patients died prior to follow-up (18%). In the surgical group there was an increase in mean LVEF from 24.0 +/- 8% to 29.7 +/- 11% (P < 0.05) while in the medical group there was a fall from 25.7 +/- 10% to 20.6 +/- 8% (P < 0.05). In group 1, the mean NYHA dyspnoea grade improved from 2.7 to 1.4 while in the medical group it was unchanged, 2.6 to 2.5. In patients with myocardial hibernation identified pre-operatively, 18/19 (95%) improved LVEF after CABG compared with 2/4 (50%) of patients without hibernation. 17/19 (86%) patients with hibernation improved NYHA dyspnoea class compared with 2/4 (50%) of patients without. 60/93 (65%) of hibernating segments improved function after revascularisation while 47/53 (89%) hibernating segments showed no improvement on medical therapy alone. CONCLUSION: In patients with severe LV impairment with myocardial hibernation, coronary artery bypass grafting improves both global and regional systolic LV function, and symptom profile. Medical treatment of patients with LV impairment and myocardial hibernation does not improve LV contractile function or symptoms. Both surgical and medical therapy carry a high mortality rate.
Adult↗
Localized intraoperative cardiac tamponade.
A 65-year-old lady had undergone mitral and aortic valve replacement following an open mitral valvotomy and aortic valve exploration 5 years earlier. At reoperation, following sternotomy, extensive adhesions were encountered and it was decided to perform minimal dissection of the heart. Both the aortic and mitral valves were replaced using 23 mm and 29 mm St. Jude bileaflet valves, respectively. At the end of the procedure it was difficult to wean the patient off bypass as her mean arterial pressure dropped and the heart became dilated. It was found that a tamponade had developed, as a result of bleeding from the vent site in the pulmonary artery, and dissected a plane between the heart and the adherent pericardium. Her condition improved dramatically as the tamponade was released and she came off cardiopulmonary bypass with no inotropic support.
Aged↗
Normothermic versus hypothermic coronary bypass surgery.
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Coronary Artery Bypass↗
Plasma 4-hydroxy-2-nonenal levels during cardiopulmonary bypass, and their relationship to the iron-loading of transferrin.
4-Hydroxy-2-nonenal (HNE) an aldehydic peroxidation produce of n-6 fatty acids, is formed predominantly in model systems when redox active transition metal ions, particularly iron, are present. During cardiopulmonary bypass surgery blood is circulated and oxygenated extracorporeally, and periods of tissue ischaemia-reoxygenation are introduced. Both events cause oxidative stress with the generation of reactive forms of oxygen leading to lipid peroxidation. During bypass iron is released often saturating plasma transferrin, and resulting in the appearance of chelatable iron in the plasma. Because such forms of iron can promote HNE formation in vitro, we have studied 12 bypass patients, 5 of whom had plasma iron-overload. Our results show a greater percentage increase in HNE formation during bypass when the plasma transferrin is iron-overloaded compared with matched controls not showing iron-overload.
Adult↗
Long term follow up of severely ill patients who underwent urgent cardiac transplantation.
OBJECTIVE: To assess long term survival (> 5 years) and quality of life in severely ill patients referred for urgent cardiac transplantation. SETTING: Tertiary referral centres: before transplantation at the National Heart Hospital (late 1984 to end 1986); after transplantation at Harefield Hospital. SUBJECTS: Eighteen patients (15 men; three women) who had required intensive support in hospital before cardiac transplantation and were alive at short term follow up. INTERVENTIONS: Intravenous infusions of cardiac drugs (mean 2.2 infusions), intravenous diuretics (17 patients), and many other drugs before transplantation. Intra-aortic balloon counterpulsation (four patients), temporary pacing (two), and resuscitation from cardiac arrest (three). Patients had specialised nursing care on a medical intensive care unit in almost every case. MAIN OUTCOME MEASURES: Long term survival in patients after urgent cardiac transplantation and perceived quality of life. RESULTS: Of 18 patients who were alive at short term follow up (mean (range) 19.4 (10-33) months), 14 were still alive in 1992 (69 (61-83) months). Ten still worked full time, and 11 reported no restrictions in their daily activities. Three of four patients who died in the intervening period survived > 5 years after transplantation. Overall, 17 of 18 patients survived at least 5 years. CONCLUSIONS: In severely ill patients who undergo urgent cardiac transplantation and survive in the short term, long term (5-7 year) survival and quality of life seem good.
Cardiomyopathy, Dilated↗
Coexistence of functioning beta 1- and beta 2-adrenoceptors in single myocytes from human ventricle.
BACKGROUND: Both beta 1- and beta 2-adrenoceptors (beta 1 AR and beta 2 AR) are present in human ventricle. This study was designed to determine whether the two subtypes contribute to contraction in single myocytes from human heart. METHODS AND RESULTS: (-)-Epinephrine increased the contraction amplitude and velocity of single myocytes isolated from the ventricles of failing and nonfailing human hearts. Concentration-response curves to (-)-epinephrine were constructed in the presence and absence of selective antagonists for beta 1 AR (CGP 20712A) and beta 2 AR (ICI 118,551). Responses to (-)-epinephrine were antagonized to a variable degree by the blockers, suggesting heterogeneous contribution of beta 1AR and beta 2AR among cells. The most common response in single myocytes was that ICI 118,551 (50 nmol/L) shifted the concentration-response curve less than 10-fold: this was lower than the 100-fold shift expected for a pure beta 2AR effect. Inclusion of CGP 20712A (300 nmol/L) with ICI 118,551 shifted the (-)-epinephrine curve still further. These observations suggest that both beta 1AR and beta 2AR contribute to the increase in contraction amplitude with (-)-epinephrine in this group of myocytes. When 300 nmol/L CGP 20712A was present as the sole antagonist, only a marginal shift of the concentration-response curve for (-)-epinephrine was usually observed, indicating that beta 1AR were not mediating the effect of these low concentrations of (-)-epinephrine. Both beta 1AR and beta 2AR mediated a considerable abbreviation of the time to peak contraction and time to 50% relaxation in the single cells. CONCLUSIONS: beta 1AR and beta 2AR coexist and function on human ventricular myocytes. At low (-)-epinephrine concentrations, contractile responses are predominantly mediated by beta 2AR rather than beta 1AR in myocytes from failing hearts.
Adrenergic beta-Antagonists↗
Role of catalase and heat shock protein on recovery of cardiac endothelial and mechanical function after ischemia.
The aim of this study was to investigate the roles of heat shock proteins and catalase after heat shock stress in the recovery of cardiac mechanical and endothelial function following a prolonged ischemic, cardioplegic arrest. Isolated working rat hearts were subjected to an ischemic cardioplegic arrest for 4 hours at 4 degrees C. Six groups, each of 6 hearts, were studied: control; control treated with 3-aminotriazole, an inhibitor of catalase; sham; sham + 3-aminotriazole; heat-shocked rats; heat shocked rats + 3-aminotriazole. Postischemic recovery of cardiac output and endothelial function (as % of preischemic control values) were respectively 54.6 +/- 1.9 and 21.2 +/- 3.0 in the control group; 52.3 +/- 2.9 and 19.1 +/- 3.9 in the control + 3-aminotriazole group; 72.2 +/- 2.7 and 54.2 +/- 7.6 in the heat shocked group; and 68.0 +/- 4.0 and 21.0 +/- 5.8 in the heat shocked + 3-aminotriazole group. SDS PAGE and western blotting showed induction of heat shock proteins in the heat stressed animals. Measurement of catalase activity showed significant inhibition in the 3-aminotriazole treated groups. It is concluded that, following heat shock stress, the enhanced endothelial recovery after prolonged ischemic cardioplegic arrest is dependent on catalase activity but that this does not apply to the recovery of mechanical functional.
Amitrole↗
Aorto-cutaneous fistula: a rare complication of aortic surgery.
Two cases of false aneurysm of the ascending aorta which presented with discharge of arterial blood from a sternal wound are discussed. The first presented 8 years after aortic valve surgery and was diagnosed by contrast enhanced computerised tomography of the thorax. The second presented 6 months following repair of an aortic dissection and the diagnosis was confirmed by thoracic magnetic resonance imaging. The diagnosis and surgical management of these cases are reviewed.
Aged↗
Infected interventricular Teflon patch: repair and closure of fistula with omentum.
A pericardiocutaneous fistula five years after repair of a rupture of the ventricular septum was managed by removing all foreign material (Teflon). The resulting defect was repaired with part of the central tendon of the diaphragm and a pedicle of omentum was used to cover the heart. This radical approach was found necessary after other measures, including surgical excision of the fistula, had failed.
Female↗