23rd Bethesda conference: access to cardiovascular care. Task Force 5: Access to cardiovascular care: an international comparison.
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Australia↗
Biomedical subjects
H E Scully
Publications and source records attributed to H E Scully.
Strut fracture with Björk-Shiley 70 degrees convexo-concave valve. An international multi-institutional follow-up study.
Between 1980 and 1983, 831 Björk-Shiley 70 degrees convexo-concave prosthetic heart valves were implanted at five institutions in Sweden, Germany. The Netherlands, and Canada. As of January 1991, there were 34 outlet strut fractures occurring from 0.2 to 10.1 years (median = 4.6 years) after implantation. In addition, there were 28 sudden, unexplained deaths. The mortality after strut fracture was 84%. The mortality after emergency valve replacement for strut fracture was 50%. The 10-year actuarial fracture rate (standard error) was 10.5 (2.4)% for large (29-33 mm) valves vs. 3.3 (1.2)% for 21-27 mm valves (P less than 0.001). Within valve size groups, fracture rates for aortic and mitral valves were similar. Cox regression analysis found only valve size to be significantly associated with strut fracture. There is a further subgrouping of the valves according to the manufacturer: group I are the earlier large 29-33 mm) valves; group II are the later large valves; group III are the small size (21-27 mm) valves. The risk of strut fracture was highest in group I (12.3% at 10 years) with an approximatively constant hazard (1.4% per year). A comparison was made with a statistical model incorporating all cases reported to the manufacturer. This model estimates fracture rates approximately 63%-73% of those found in the present study. These findings lead us to recommend that group I patients should be considered for elective reoperation on an individual basis, giving careful attention to risk factors and contraindications.
Adolescent↗
Medicare: the Canadian experience.
In the 1940s Canada and the United States had similar lack of structure and reimbursement for diagnostic, hospital, and physician services. In Canada over the next 40 years there evolved a complex system mandated and partially funded by the federal government, but administered and delivered through 10 provincial and 2 territorial jurisdictions. Each must negotiate with federal government on cost sharing and deal with hospital budgets and physician compensation at the provincial or territorial level. The Medical Care Act of 1966 enshrined in law the five principles of public administration, universality, comprehensiveness, portability, and accessibility, converting all medical services in Canada from a privilege to a right. Any patient participation in hospital or physician charges came under increasing political attack. In 1984 the Canada Health Act specified financial penalties in federal transfer payments to provinces that permitted any direct patient charges. While Canada has "contained" health expenditures at 8.7% of gross national product, universal access to quality care is increasingly subject to rationing. The relationship between the profession and governments hard pressed to fund escalating costs in a deteriorating economy has been one of increasingly bitter confrontations. There have been four acrimonious doctors' strikes. More optimistically, there is now an emerging recognition of society's need to have physicians actively participating with other providers and governments to create a balance between access to quality health services and both public and private funding.
Canada↗
Thoracic aortic surgery.
Between 1982 and 1989, 119 patients had repair of thoracic aortic pathology. Thirty-seven had repair of ascending aortic aneurysms, with an 11% hospital mortality. Forty-one patients had urgent repair of acute type A aortic dissections, with a 32% hospital mortality. The independent predictors of mortality were the use of crystalloid cardioplegia, aortic dissection, and the use of an intraluminal prosthesis or the inclusion surgical technique. Better grafts and the resection technique has reduced mortality since 1986. Seventeen patients had their primary pathology in the aortic arch, with a 47% hospital mortality. The urgency of the procedure and crystalloid cardioplegia predicted an unsuccessful outcome. Seventeen patients had descending aortic aneurysms repaired, with an 18% mortality. The urgency of surgery was the predictor of mortality. Seven patients had a descending thoracic aortic disruption repaired, with one death (14%). Better graft materials, surgical techniques, and methods of myocardial protection have contributed to the improved results of thoracic aortic surgery in recent years.
Aortic Dissection↗
HSOs: Ontario's answer to HMOs?
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Capitation Fee↗
Hormonal and metabolic responses during coronary artery bypass surgery: role of infused glucose.
Anesthesia, surgery, and hypothermia are conventionally considered the major stress factors in the metabolic and hormonal responses to cardiac surgery. We compared these responses in 14 nondiabetics during and for 24 h after coronary artery bypass surgery; 8 received cardioplegic solutions (C+), and 6 did not (C-). The mean intraoperative glucose load in C+ was 106 g compared to 32 g in C-; postoperatively both groups received 50 g. Marked hyperglycemia (31.8 +/- 4.8 mmol/L) occurred during hypothermia in C+, but dropped to 18.9 mmol/L before surgery ended and to 11.2 +/- 1.1 mmol/L by 2 h postop. In contrast, C- showed constant mild hyperglycemia of 8.3-9.8 mmol/L throughout, significantly less than C+ until 1 h postop. Insulin was suppressed by 55% only during hypothermia, peaking with rewarming in C+ at 2,849 +/- 911 vs. 639 +/- 251 pmol/L in C- (P less than 0.05); as with glycemia, values were comparable after 2 h postop. The pancreatic beta-cell thus responded to hyperglycemia during restoration of normothermia, resulting in a rapid decline in glycemia. This occurred despite elevations in antiinsulin factors in both groups; GH was 14 +/- 4 micrograms/L, cortisol was 607 +/- 38.6 nmol/L, norepinephrine was 11.5 +/- 3.7 nmol/L, epinephrine was 13,863 +/- 3,875 pmol/L, and FFA were 0.36 +/- 0.05 g/L. Early postop, a secondary rise in stress hormones occurred in both groups. Maximal cortisol values were at 4 h (1,186 +/- 140 nmol/L) and peaks of norepinephrine (6.50 +/- 1.66 nmol/L), epinephrine (7,969 +/- 3,602 pmol/L), and FFA (0.27 +/- 0.03 g/L) occurred. The only significant glucagon elevation was at 24 h (C+, 464 +/- 53 ng/L; C-, 350 +/- 241 ng/L; P less than 0.02), Thus, 1) many metabolic responses during coronary artery bypass surgery are influenced by the glucose-containing cardioplegic solution; 2) hypothermia suppresses insulin secretion, but it responds thereafter despite marked elevations of catecholamines, and is associated with decreasing glycemia despite elevated antiinsulin factors; 3) a lesser but highly significant stress response corresponds to awakening from anesthesia; and 4) glucagon plays a minor role in intraoperative hyperglycemia; the rise at 24 h is unexplained.
Aged↗
Outlet strut fracture of the Björk-Shiley 60 degrees Convexo-Concave valve: current information and recommendations for patient care.
Mechanical failure of artificial heart valves can be a catastrophic event. The problem of outlet strut fracture of the Björk-Shiley 60 degrees Convexo-Concave tilting disc prosthesis has received much attention in the medical literature and generated both concern and confusion among patients and physicians. Analysis of current data from the manufacturer, as well as a review of the medical literature, suggests that the overall risk of outlet strut fracture is low and that elective explantation of a well functioning Björk-Shiley 60 degrees Convexo-Concave valve prosthesis is not warranted. Diagnostic features of outlet strut fracture can be seen with overpenetrated chest X-ray films so that diagnosis can be established promptly. Early operation to replace the fractured prosthesis is essential for patient survival.
Aortic Valve↗
Clinical performance of Bjork-Shiley mechanical heart valves: a perspective on outlet strut fractures in the 60 degrees and 70 degrees convexo-concave disc models.
The convexo-concave disc model of Bjork-Shiley mechanical heart valve is a significant improvement over the spherical disc model and compares favourably to other valves, including bioprostheses, with respect to hemodynamics, thromboembolism, anticoagulant related hemorrhage and prosthetic endocarditis. A small number of the 60 degrees and 70 degrees welded outlet strut Bjork-Shiley convexo-concave valves are at risk of sudden structural failure. The risk is constant or decreasing with time. Elective explanation is not recommended. The integral outlet monostrut 70 degrees Bjork-Shiley convexo-concave valve demonstrates further improvements in design and durability, and is recommended for use in patients who are appropriate candidates for mechanical cardiac prostheses.
Aortic Valve↗
The determinants of mortality and morbidity after multiple-valve operations.
The factors predictive of hospital mortality and morbidity after contemporary multiple-valve surgical procedures were identified to develop strategies to improve the results of such procedures. Preoperative, intraoperative, and postoperative information was collected prospectively on 90 consecutive patients undergoing surgical procedures between 1982 and 1984. The operative mortality was 5.6%, and the incidence of postoperative low-output syndrome was 16.7%. Multivariate logistic regression analysis identified tricuspid regurgitation (p less than .03, improvement-of-fit chi square) and the aortic valve lesion (p less than .03) as the independent predictors of postoperative complications (mortality or low-output syndrome). Patients with tricuspid regurgitation and right ventricular decompensation and those with aortic stenosis and left ventricular hypertrophy had limited ventricular functional reserve and faced an increased risk. Improved methods of myocardial protection may reduce the risk in these patients.
Adult↗
Increased risk of urgent revascularization.
To determine the risk factors for operative mortality and morbidity, we performed a prospective analysis of 1,980 patients undergoing isolated coronary artery bypass operations between 1982 and 1984. The operative mortality was 3.5%, and the incidence of perioperative myocardial infarction was 8.6% and low output syndrome, 12.0%. Stepwise logistic regression identified sex, preoperative left ventricular ejection fraction, and the urgency of operation as independent risk factors for postoperative mortality. Urgent revascularization was performed in patients with unstable angina refractory to maximal medical therapy. In these patients the operative mortality was 8.5%. Independent risk factors of postoperative morbidity, in addition to sex, ejection fraction, and urgent revascularization, included a previous bypass procedure, age, and New York Heart Association functional class. Unstable angina unresponsive to medical therapy contributed significantly to the operative risk. Interventions to reduce perioperative ischemic injury, such as improved methods of myocardial protection, may improve the results in high-risk patients.
Cardiac Output, Low↗
Can the results of contemporary aortic valve replacement be improved?
Although the results of contemporary aortic valve replacement are excellent, cardiac surgeons must identify the factors that predict postoperative morbidity and mortality to develop alternative strategies for high-risk patients. Two hundred seventy-seven consecutive patients undergoing isolated aortic valve replacement between 1982 and 1984 were evaluated. Thirty-seven clinical and 13 preoperative hemodynamic variables were analyzed by univariate and multivariate statistics to determine the risk factors for postoperative morbidity and mortality. The operative mortality was 3%, the incidence of a postoperative low output syndrome was 12%, and the incidence of a perioperative myocardial infarction was 5%. A multivariate, logistic regression analysis found that age was the only the only independent predictor of mortality. Three factors independently predicted postoperative low output syndrome: age, the presence of coronary artery disease, and the peak systolic gradient in patients with aortic stenosis. Patients with aortic stenosis had a higher incidence of postoperative ventricular dysfunction (17%) than those with mixed valvular disease (9%) or aortic regurgitation (5%). Perioperative myocardial infarction was predicted by the extent of coronary artery disease. The incidence of perioperative myocardial infarction was higher in patients with triple-vessel coronary artery disease (13%) and those with left main stenosis (18%) than in patients with single- or double-vessel disease (4%) or those without coronary artery disease (4%). Because of the higher risk of aortic valve replacement in older patients, the risk-benefit ratio of the operation must be carefully assessed in the elderly. Improved methods of myocardial protection may reduce the risks for patients with aortic stenosis and symptomatic triple-vessel coronary artery disease.
Adult↗
Comparison between antibiotic irrigation and mobilization of pectoral muscle flaps in treatment of deep sternal infections.
Between January of 1978 and December of 1983, 41 patients developed deep sternal infections with mediastinitis after cardiac operations. Between January of 1978 and December of 1981, 19 of these patients were treated with débridement, primary wound closure, and mediastinal antibiotic irrigation (Group I). Between January of 1982 and December of 1983, 22 patients were treated with débridement, open "clean" packing, and delayed wound closure by the technique of pectoral muscle flap mobilization, which preserves the thoracoacromial pedicles and the pectoral humeral attachments (Group II). The purpose of this study was to compare the results of the treatment of deep sternal infections after cardiac operations with these two techniques. The perioperative hemodynamic, operation, functional, and pathological profiles of both groups of patients were the same. The cosmetic and functional results were the same in both groups as were shoulder girdle and torso mobility. We conclude that either technique is equally effective in the management of patients in whom the serious complication of deep sternal infection with mediastinitis develops after cardiac operation, and we now recommend débridement and pectoral muscle flap closure in one stage.
Anti-Bacterial Agents↗
Thrombosis of a prosthetic valve managed by thrombolysis: a case report.
Thrombosis of a prosthetic valve is one of the most serious cardiovascular events. Emergency replacement of the prosthetic valve has been the standard method of management but carries a high operative risk. This paper describes the successful use of streptokinase, given intravenously, to manage a patient with this complication in the acute phase. Eventually, operation was necessary because the presence of residual organized clot was suspected, but the procedure was performed electively 10 days later.
Adult↗
Morbidity and mortality in mitral valve surgery.
To develop strategies for the management of high-risk patients, contemporary risk factors for operative mortality and postoperative ventricular dysfunction were identified in 214 patients undergoing mitral valve surgery in 1982 and 1983. Thirty-eight preoperative and perioperative variables were prospectively collected and analyzed by univariate and multivariate statistics. The overall mortality was 4.6% and the incidence of postoperative low-output syndrome (LOS) was 18.7%. Forty-seven patients with coronary artery disease (CAD) had a higher mortality and incidence of LOS (as evidenced by the need for inotropic drugs or counterpulsation to maintain blood pressure) (those with CAD 15% mortality, 40% LOS; those without CAD 2% mortality, 13% LOS; p less than .05). The presence of unstable angina and ischemic mitral regurgitation further increased the risk. Age was also a predictor of outcome. Patients who died or had LOS were older (those who died, 65 +/- 7 years, those with LOS, 58 +/- 11 years) than patients who survived and did not have postoperative dysfunction (those who survived, 53 +/- 11; those with no LOS, 53 +/- 11; p less than .01). Mitral regurgitation was associated with a higher (p less than .05) mortality and incidence of LOS (mortality 10.5%, LOS 36%; n = 76) than was mitral stenosis (mortality 0%, LOS 4%; n = 74) or mixed lesions (mortality 3%, LOS 15%; n = 64). In patients without CAD, mitral regurgitation remained a significant predictor of mortality and ventricular dysfunction.(ABSTRACT TRUNCATED AT 250 WORDS)
Adult↗
Permanent cardiac pacing after open-heart surgery: acquired heart disease.
Retrospective review of 5,942 patients who underwent open-heart surgery for acquired heart disease revealed that 123 patients (2.1%) required permanent cardiac pacing postoperatively; 4.6% of these underwent predominantly valvular surgery and 0.6% had coronary bypass. The most important factors appeared to be: 1) preoperative evidence of a conduction disorder; 2) advanced patient age; 3) dense calcium in the aortic annulus; 4) valvular surgery and, especially, tricuspid valve surgery; and 5) poor myocardial protection. Postoperative permanent pacing had a considerable impact on patient morbidity from maintenance operations; most complications were lead-related problems.
Adult↗
Limitations of blood conservation.
Blood conservation has been most successful when blood salvage techniques have been combined with postoperative normovolemic hemodilution. The hemodynamic and myocardial metabolic responses to normovolemic hemodilution were assessed in a prospective randomized trial. Twenty-seven patients were randomized to receive either blood and colloid solutions (colloid group, 13 patients) or crystalloid fluids (crystalloid group, 14 patients) following elective coronary revascularization. Although seven patients in the crystalloid group received blood products when the hemoglobin level fell below 7 gm/dl, blood bank requirements were less in the crystalloid group (colloid, 3.6 +/- 1.2 L; crystalloid, 1.5 +/- 1.0 L, p less than 0.01). The crystalloid group received twice as much fluid to maintain normovolemia (left atrial pressure between 8 and 10 mm Hg) in the first 72 hours postoperatively (colloid, 6.5 +/- 1.9 L; crystalloid, 14.5 +/- 3.1 L, p less than 0.01). The infusion of large volumes of crystalloid fluids resulted in a progressive postoperative anemia (hemoglobin: colloid, 12.1 +/- 1.6 gm/dl, crystalloid 8.9 +/- 1.7 gm/dl, p less than 0.01, 20 hours postoperatively). Although the crystalloid-treated patients had peripheral edema, pulmonary edema could not be documented and there was no difference in the physiological shunt fractions between the two groups. Preload (left atrial pressure), afterload (mean arterial pressure), and cardiac index were similar in the two groups. The crystalloid group had a delayed recovery of myocardial oxygen and lactate extraction postoperatively. Volume loading and atrial pacing 3 to 5 hours postoperatively maintained myocardial lactate extraction in the colloid group but decreased myocardial lactate extraction to ischemic levels in the crystalloid group. The use of crystalloid rather than colloid fluids in the early postoperative period conserved blood products but resulted in postoperative anemia and was associated with a delay in myocardial metabolic recovery. Normovolemic hemodilution should be employed with caution in patients who are at risk of perioperative ischemic injury.
Blood Transfusion↗
A comparison of volume loading and atrial pacing following aortocoronary bypass.
Although cold potassium cardioplegia provides adequate myocardial protection, transient hemodynamic and metabolic instability occasionally occurs after uncomplicated coronary bypass surgery. Two methods to increase cardiac output were compared 2 to 6 hours postoperatively in 24 patients recovering from elective coronary bypass operation. Volume loading increased cardiac index (CI) from 2.1 +/- 0.5 to 2.7 +/- 0.6 L/min/m2 by increasing left atrial pressure (LAP) from 8.6 +/- 3.6 to 13.0 +/- 4.1 mm Hg. Atrial pacing at a rate of 112 +/- 8 beats per minute increased CI from 2.4 +/- 0.5 to 2.7 +/- 0.8 L/min/m2 without a change in LAP. Ejection fraction by nuclear angiography did not change, but the calculated left ventricular end-diastolic volume index (stroke index/ejection fraction) increased with volume loading and decreased with atrial pacing--a decrease in diastolic compliance. Myocardial oxygen extraction did not change, but myocardial lactate extraction increased with volume loading and decreased with atrial pacing. Coronary sinus blood flow was measured in 5 patients and increased with both methods studied. Volume loading demonstrated that myocardial performance was normal and myocardial metabolism increased commensurate with the increase in work. Atrial pacing increased CI but resulted in anaerobic metabolism and a decrease in diastolic compliance. Volume loading rather than atrial pacing will improve CI without producing ischemia in the early postoperative period.
Adult↗