Reoperative coronary bypass surgery: effect of patent grafts and retrograde cardioplegia.

OBJECTIVE: To determine the effects of patent or diseased aorta-coronary bypass grafts and retrograde cardioplegia on mortality during reoperative coronary bypass surgery. METHODS: We conducted a retrospective review of prospectively gathered data, supplemented by systematic chart review, of all patients (n = 744) undergoing reoperative coronary bypass surgery at our institution between 1990 and 1997. Independent predictors of survival were determined by stepwise logistic regression analysis. RESULTS: At least one patent or stenosed graft to the left anterior descending artery was present in 50% of patients, to the circumflex territory in 27% of patients, and to the right coronary artery territory in 33% of patients. The previous left anterior descending graft was a saphenous vein in 82% and a left internal thoracic artery in 18% of patients. In-hospital mortality occurred in 42 (5.6%) patients. Patent or diseased grafts of any coronary artery territory did not significantly increase the risk of mortality. Retrograde cardioplegia use increased in more recent years, was more frequent in patients with stenosed grafts, and was associated with improved survival. Independent predictors of mortality were as follows (with odds ratios and 95% confidence intervals in parentheses): failure to use retrograde cardioplegia (odds ratio 2.81; 1.28-6.20), New York Heart Association class (odds ratio 2.69; 1.25-5.81), peripheral vascular disease (odds ratio 2.60; 1.25-5.41), and left ventricular grade (2.07; 1.31-3.27). CONCLUSIONS: In this series, patent or stenosed grafts were not associated with an increased risk of mortality during reoperative coronary bypass surgery, possibly because of increased use of retrograde cardioplegia in this patient group. We strongly recommend the routine use of retrograde cardioplegia during redo coronary bypass surgery.

Aortic valve replacement with stentless and stented porcine valves: a case-match study.

OBJECTIVES: To assess the potential benefits of the hemodynamic superiority of stentless valves, we conducted a case-match study among patients who underwent aortic valve replacement with two types of porcine bioprostheses: the Toronto SPV and the stented Hancock II bioprosthesis. METHODS: Preoperative clinical variables predictive of death after aortic valve replacement were determined by a stepwise logistic regression analysis in a series of 908 consecutive patients who received porcine aortic bioprostheses during a 14-year interval. Advanced age, New York Heart Association functional class IV, left ventricular ejection fraction of less than 30%, and coronary artery disease were independent predictors of death. On the basis of these four variables, 198 pairs of patients who survived aortic valve replacement with stentless and stented porcine valves were matched. The follow-up, truncated to the shortest interval for each matched pair, was 43 +/- 24 months for both groups. RESULTS: At 8 years the actuarial survival was 91% +/- 4% for the Toronto SPV group and 69% +/- 8% for the Hancock II group (p = 0.006); the freedom from cardiac-related death was 95% +/- 4% for the Toronto SPV and 81% +/- 8% for the Hancock II (p = 0.01); the freedom from any valve-related complication was 81% +/- 5% for the Toronto SPV and 50% +/- 10% for the Hancock II (p = 0.008). A Cox proportional hazard model demonstrated a significant reduction in cardiac mortality rates and valve-related morbidity in patients who received the Toronto SPV bioprosthesis. CONCLUSIONS: Although it is possible that confounding factors may have played a role in the clinical outcomes of this case-control study, the study suggests that aortic valve replacement with a stentless porcine valve enhances survival. This is believed to be due to the hemodynamic superiority of these valves.

Aortic valve replacement with stentless porcine aortic valves: a ten-year experience.

BACKGROUND AND AIMS OF THE STUDY: It has been shown that although stentless porcine aortic valves have better hemodynamic features than stented porcine valves, their long-term durability remains unknown. This study was undertaken to examine the long-term clinical outcome of aortic valve replacement (AVR) with stentless porcine aortic valves. METHODS: Between 1987 and 1989, custom-made stentless valves were implanted in 29 patients (mean age 58 years), and between 1991 and 1997, the Toronto SPV was implanted in 213 patients (mean age 63 years). In addition to AVR, one-third of the patients had coronary artery bypass. All patients were followed up at annual intervals and underwent Doppler echocardiography. RESULTS: There were two operative and 11 late deaths (four cardiac, seven non-cardiac). The actuarial survival rate was 89 +/- 4% at nine years. There were two strokes and seven transient ischemic attacks; freedom from thromboembolic complications was 92 +/- 4% at nine years. Two patients developed infective endocarditis, one early and one late; freedom from prosthetic valve endocarditis was 98 +/- 1% at nine years. Freedom from primary tissue failure was 85 +/- 8% at nine years. Seven patients required repeat AVR, because of endocarditis (two) and aortic insufficiency (five); freedom from repeat AVR was 82 +/- 8% at nine years. Periodic hemodynamic assessment by echocardiography indicated that the mean systolic gradients across the valve decreased during the first year of implantation, the valve effective orifice increased, and valve competence remained stable. CONCLUSIONS: Stentless porcine aortic valves have provided excellent clinical results. These valves may suffer degenerative changes and fail at the same rate as stented porcine aortic valves but, because of their superior hemodynamic performance, they may enhance patients' survival by allowing complete regression of left ventricular hypertrophy and restoration of normal ventricular function.

Deep sternal wound infection: risk factors and outcomes.

BACKGROUND: Deep sternal wound infection (DSWI) is a serious complication of cardiac operations performed by median sternotomy. We attempted to define the predictors of DSWI and to describe the outcomes of two treatment strategies used at our institution. METHODS: Retrospective review was performed using prospectively gathered data on 12,267 consecutive cardiac surgical patients from 1990 to 1995. Chart review was performed on all patients in whom DSWI developed, and follow-up was obtained on 100% of these patients. RESULTS: Deep sternal wound infections developed in 92 patients (incidence 0.75%). Multivariable predictors for development of DSWI in all patients were (odds ratios and 95% confidence intervals in parentheses) (1) diabetes mellitus (2.6; 1.7 to 4.0) and (2) male sex (2.2; 1.3 to 3.9). In patients receiving coronary artery bypass grafting alone, independent predictors were (1) bilateral internal thoracic artery grafts (3.2; 1.1 to 8.9), (2) diabetes (2.7; 1.6 to 4.3), and (3) male sex (1.8; 0.9 to 3.7). For all other patients, predictors were (1) age more than 74 years (3.3; 1.1 to 10.1), (2) male sex (3.0; 1.1 to 8.1), and (3) diabetes (2.3; 0.9 to 5.8). Bilateral internal thoracic artery grafts increased the risk of DSWI in all subgroups of coronary artery bypass graft patients, particularly in diabetics who had a 14.3% incidence of DSWI after bilateral internal thoracic artery grafting. Patients with DSWIs received either sternal debridement with primary closure (n=45) or sternectomy with flap reconstruction (n=46). The 6-month freedom from adverse event rate (ie, readmission, reoperation, or death) was 76% for both groups of patients. CONCLUSIONS: Male sex and diabetes are predictors of DSWI in all cardiac surgical patients. Bilateral internal thoracic artery grafting may be contraindicated in diabetic patients.

Cardiac surgery in a fixed-reimbursement environment.

Hospital and physician services in Canada are funded by public (government) sources. This article will describe the practice of cardiac surgery in this setting. Federal legislation has prescribed the principles of accessibility, universality, comprehensiveness, portability, and public administration for essential healthcare services in Canada. Provincial and territorial governments are responsible for the provision of services, receiving federal tax and cash transfers that supplement provincial/territorial funds for hospital, physician, and community health services. Hospitals negotiate annually for global budgets. Physicians work as independent contractors in hospitals (and communities) and are usually paid as specified by fee-for-service contracts negotiated at intervals with governments. Cardiac surgical services have been planned conjointly with government. Forty-two centers in Canada serve a population of 28 million. All but three of these centers are located in tertiary teaching hospitals; all but one do more than 200 pumps annually. The rate of cardiac operations is 80 per 100,000 population. In Ontario, the Provincial Adult Cardiac Care Network makes recommendations to governments about the distribution of the 7,600 pumps annually (population, 11 million), rationalizing waiting lists based on an urgency rating scale. Patients requiring emergent/urgent operations are well served. The average waiting time for an elective cardiac operation is 10.5 weeks. The waiting list mortality is less than 0.5%. The Provincial Adult Cardiac Care Network also determines the placement of new programs and participates in creating hospital funding formulas developed from a combination of resource and acuity intensity weighting. Most surgeons hold full-time academic appointments but are funded largely by practice income. Surgical fees average $2,000 (Canada) per case. Overhead, including malpractice insurance, is approximately 45%. All Canadian patients enjoy reasonably timely access to good cardiac surgical care. Further constraints on physician compensation and (academic) hospital funding will compromise this balance.

Tricuspid valve replacement. Fifteen years of experience with mechanical prostheses and bioprostheses.

Tricuspid valve replacement is not a common operation. The purpose of this study was to examine the early and late results in 60 patients who underwent 28 (47%) bioprosthetic and 32 (53%) mechanical tricuspid valve replacements. All operations took place between January 1978 and June 1993 during which period a total of 4741 patients underwent valve replacement operation. Mean patient age was 50 +/- 15 (18 to 75) years. Forty-one patients (68%) were female and 19 patients (32%) were male. Forty-nine patients (82%) were in New York Heart Association class III or IV before operation. Forty-five patients (75%) were undergoing repeat cardiac valve operation. Seventeen patients (28%) had complex congenital cardiac problems. Operation was urgent in 15 patients (25%). The hospital mortality rate was 27% (16 patients). All patients with hospital death were in New York Heart Association class III or IV, were having repeat operations, or had complex congenital disease. Low output syndrome was observed in 21 patients (35%). Reoperation because of bleeding was required in seven patients (12%). Thirteen patients (22%) required permanent (epicardial lead) pacemaker implantation. Mean follow-up is 75 +/- 45 months (maximum 173 months) and 100% complete for the 44 patients who left the hospital. There have been 14 deaths (32%). Nine of these patients (64%) had mechanical valves and five (36%) had bioprostheses. Of the 11 cardiac deaths, three were valve related (bioprostheses). Three patients (10%) required reoperation because of tricuspid valve prosthetic failure (1 thrombosed mechanical valve, 2 failed porcine valves). Of the remaining 30 patients, 20 (67%) are in New York Heart Association class I or II. Seventeen patients have mechanical valves and 13 have bioprostheses. Twenty-six patients (90%) are receiving warfarin. Thromboembolism (transient ischemic attack) has occurred in one patient with a mechanical valve who also had a previous cerebrovascular accident. In this group there has been no hemorrhage, endocarditis, or new pacemaker requirement. Actuarial survival for the whole series is 37% +/- 9% and for the hospital survivors is 50% +/- 12% at 15 years. Linearized rates of valve-related complications are not different between groups. Tricuspid valve replacement is a beneficial procedure for patients with structural tricuspid valve disease, many of whom have other valvular or congenital disease. Contemporary mechanical prostheses and bioprostheses are equally effective in the tricuspid position. Mechanical valves should be considered for tricuspid replacement in young patients and in patients with mechanical valves implanted in the left side of the heart.

Spontaneous spinal epidural hematoma in a patient with a mechanical aortic valve taking warfarin.

A 59-year-old male with a mechanical aortic valve taking warfarin presented to hospital with Brown-Séquard syndrome caused by a spontaneous spinal epidural hematoma (SSEH) precipitated by a coughing fit. Guided by a literature review of the risks of administering or withholding anticoagulation in this patient, doctors advised a regimen of warfarin to achieve an international normalized ratio of 1.5 to 2 and dipyridamole (75 mg qid) to protect against thromboembolic complications while minimizing the risk of recurrent SSEH.

Aortic valve replacement with a stentless porcine aortic valve. A six-year experience.

A stentless porcine aortic valve was used for aortic valve replacement in 123 patients from 1987 to 1993. The mean age of 86 men and 37 women was 61 +/- 12 years. Most patients had aortic stenosis; one-third had coronary artery disease and six had mitral valve disease. The stentless valve was secured in the subcoronary position by the same technique used for a freehand aortic valve homograft. The size of valve was based largely on the diameter of the sinotubular junction of the aortic root. The mean valve size was 26.5 mm (range 19 to 29 mm) and 87% were 25 mm or larger. Two operative deaths occurred, one the result of myocardial infarction and the other the result of infective endocarditis. Patients have been followed up from 3 to 77 months, mean 22 months. Three late deaths, none related to the valve, have occurred. The actuarial survival at 6 years was 91% +/- 4%. Four transient cerebral ischemic events have occurred, but two patients had extracranial cerebrovascular disease. One patient had endocarditis late in the postoperative period and required reoperation. All patients had Doppler echocardiographic studies before discharge from the hospital, 3 to 6 months later and annually. Only 15 patients have aortic insufficiency, trivial in 6 and mild in 9. The peak and mean systolic gradients decreased significantly during the first 3 to 6 months after implantation (p < 0.001), and the effective valve areas increased significantly during this time interval (p < 0.001). This improvement in valve hemodynamics is believed to be due to remodeling of the aortic root and regression of left ventricular hypertrophy. The results of aortic valve replacement with this stentless bioprosthesis have been excellent and justify its continued use in older patients.

Assuring the affordability of Canada's health care system.

Canada's health care system is challenged by a crisis of affordability. A sluggish economy and substantial federal, provincial, and territorial debt have caused health care spending, in spite of a good record of cost control, to consume nearly 10% of Canada's gross domestic product, largely due to a denominator effect. Issues identified as warranting further investigation as potential approaches to further reducing cost in order to match available resources include therapeutic effectiveness, drug use, hospital utilization, manpower planning, consumer access, and population approaches to improving health status. An important role exists for clinical investigators to contribute to health care reform.

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.

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.

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.