Coronary artery disease and coronary artery bypass grafting in diabetic patients aged > or = 65 years (report from the Coronary Artery Surgery Study [CASS] Registry)

A cohort of 317 diabetic patients, aged > or = 65 years, with angiographically proven coronary artery disease, was analyzed and followed for a mean of 12.8 years. Compared with 1,843 age-matched nondiabetic patients, diabetic patients were more likely to (1) have a higher number of coronary occlusions, (2) not be current smokers, (3) have higher systolic but lower diastolic blood pressures, (4) have evidence of peripheral vascular disease, and (5) be women. They did not differ significantly with respect to total cholesterol, family history of coronary artery disease, history of hypertension, or left ventricular hypertrophy. In the total elderly cohort, diabetes was found to be an independent predictor of mortality, conferring a 57.0% increased risk of death. Survival analysis showed that diabetic subjects consistently had higher mortality than nondiabetics. However, the relative survival benefit of coronary artery bypass graft surgery versus medical therapy was comparable in diabetic and nondiabetic patients. Surgical therapy conferred a reduction in mortality of 44%.

Long-term survival in patients with coronary artery disease: importance of peripheral vascular disease. The Coronary Artery Surgery Study (CASS) Investigators

OBJECTIVES

The purpose of this study was to determine the importance of peripheral arterial disease in predicting long-term survival in patients with clinically evident coronary artery disease.

BACKGROUND

Patients in the Coronary Artery Surgery Study (CASS) Registry were followed up for > 10 years.

METHODS

Survival in 2,296 patients with peripheral arterial disease was compared with that of 13,953 patients without peripheral arterial disease using Kaplan-Meier survival curves. All patients had known stable coronary artery disease. Clinical, electrocardiographic (ECG), chest X-ray film and catheterization variables of the two groups were compared using the chi-square statistic or the two-sample t test. The independent effect of peripheral arterial disease (as well as other variables) on mortality was determined utilizing a Cox proportional hazards model.

RESULTS

Patients with peripheral vascular disease were more likely to have hypertension, diabetes, family history of coronary artery disease, previous angina or myocardial infarction, previous coronary bypass surgery or to have smoked. They also had a higher incidence of congestive heart failure, ECG abnormality and modestly increased frequency of three-vessel disease. Independent correlates of long-term mortality for the entire cohort included age, smoking, diabetes, number of diseased coronary vessels, left ventricular function, hypertension, pulmonary disease, anginal class, previous myocardial infarction and peripheral vascular disease (all p < 0.001). At any point in time, patients with peripheral vascular disease had a 25% greater likelihood of mortality than patients without peripheral vascular disease (multivariate chi-square 25.83, hazard ratio 1.25, 95% confidence interval 1.15 to 1.36, p < 0.001).

CONCLUSIONS

Peripheral vascular disease is a strong, independent predictor of long-term mortality in patients with stable coronary artery disease. Aggressive attempts at secondary disease prevention are warranted in this high risk group.

Five-year angiographic follow-up of factors associated with progression of coronary artery disease in the Coronary Artery Surgery Study (CASS). CASS Participating Investigators and Staff

OBJECTIVES

The Coronary Artery Surgery Study (CASS) required participants to undergo follow-up angiography at 5 years to identify clinical and angiographic features associated with progression of coronary artery disease.

BACKGROUND

The CASS randomized 780 patients at 11 participating clinical centers between an initial strategy of medical therapy versus bypass surgery. Five clinical sites accomplished follow-up angiography in > 50% of their randomized subjects within a 42- to 66-month period after the entry arteriogram (n = 314).

METHODS

Qualified clinical site angiographers, using side by side film review, evaluated an average of 13 segments/patient on both arteriograms for initial stenosis severity, morphologic features, lesion location and occurrence of disease progression or occlusion. Progression was defined as further definite narrowing by > or = 15% and occlusion as lesion progression to > or = 98%. Lesions were subcategorized as to whether they were univariate and had or had not been treated with bypass surgery. Multivariate logistic regression analyses were performed.

RESULTS

For nonbypassed segments, right coronary artery and left anterior descending artery proximal and midlocations were associated with disease progression. For stenosis-containing segments, the initial severity, a non-left anterior descending artery location and increased treadmill duration predicted progression. Segment occlusion was associated with initial lesion severity, right coronary artery location and subsequent interval myocardial infarction. There were few predictors of progression or occlusion in bypassed arteries, other than initial lesion severity.

CONCLUSIONS

Univariate and multivariate associations with lesion progression and occlusion included diabetes, lesion location, elevated cholesterol level, interval infarction and lesion morphology. These angiographic results, collected in a prospective trial, are consistent with known risk factors.

Diagnosis of sternal wound infection by technetium-99m-leukocyte imaging

An imaging study is needed that can detect sternal wound infections and distinguish between superficial and deep sternal wound infection when a clinical diagnosis is uncertain and a decision regarding surgical intervention must be made. We retrospectively reviewed the 99mTc-leukocyte scans of 29 patients referred to rule out sternal wound infection. The presence or absence of deep or superficial sternal wound infection was determined by microbiology and long-term follow-up. Images obtained 4 and 20 hr after injection were reviewed by two nuclear physicians who were blinded to the clinical history. Findings were categorized as normal or abnormal. Abnormal images were further defined as having intense uptake at 4 and 20 hr, increasing uptake between 4 and 20 hr, or other patterns such as focal cold regions, irregular uptake at 4 and 20 hr or increasing uptake between 4 and 20 hr were 100% sensitive and 89% specific for the detection of deep sternal wound infection. The images were also useful for determining the extent of infection. Superficial sternal wound infection could not be reliably detected. The results indicate that 99mTc-leukocyte imaging is useful for the diagnosis of deep sternal wound infection.

Plasma fibronectin levels during cardiopulmonary bypass

Plasma fibronectin, also called cold-insoluble globulin, is a cryoprecipitable glycoprotein with both opsonic and adhesive activities. It binds to collagen, actin, and heparin and can form soluble as well as cryoprecipitable complexes in the cold. Fibronectin augments particulate phagocytosis by the reticuloendothelial system and can influence lung vascular permeability. Plasma fibronectin deficiency is temporally associated with respiratory failure in septic surgical, trauma, and burn patients. We measured plasma fibronectin and albumin levels in nine adults undergoing elective cardiopulmonary bypass to determine whether dilution alone could account for the changes in plasma fibronectin. Plasma fibronectin concentration decreased 17% with the surgical trauma of opening of the chest and placement of the vascular cannulas. On heparinization and initiation of cardiopulmonary bypass, plasma fibronectin fell an additional 48% (P less than 0.001), whereas albumin concentration (corrected for albumin in the pump prime) fell only 25% (P less than 0.001), emphasizing that dilution was not the only mechanism contributing to the decline in plasma fibronectin. Fibronectin levels began to increase after discontinuation of cardiopulmonary bypass and in association with diuresis, but unexpectedly they remained subnormal until 4 days postoperation. Thus the decline in fibronectin concentration with cardiopulmonary bypass may be due to dilution as well as opsonic consumption and possible complexing with heparin in the cold.

Coronary Artery Surgery Study (CASS): comparability of 10 year survival in randomized and randomizable patients

The Coronary Artery Surgery Study (CASS) includes 780 patients with mild or moderate stable angina pectoris or asymptomatic survivors of a myocardial infarction who were randomized to either medical or surgical therapy and 1,319 patients who were eligible for randomization but were not randomized (randomizable patients). There were no substantial aggregate differences observed in any of the survival comparisons after 10 years of follow-up study between the randomized and randomizable patients assigned to the medical (79% versus 80%) or surgical (82% versus 81%) groups or in patient subgroups stratified according to coronary artery disease extent and left ventricular ejection fraction. Cox regression analyses were done with independent variables known to be predictors of survival, including surgical versus medical therapy and randomized versus randomizable group, to test the null hypothesis of a mortality difference between medical versus surgical assignment according to group assignment (randomized versus randomizable). In no case did the initial group category enter as a significant predictor of survival. The results in the randomizable group reinforce those in the randomized group with respect to the medical versus surgical comparison. Two subgroups are identified with a significant surgical advantage: 1) patients with proximal left anterior descending coronary artery stenosis greater than or equal to 70% and an ejection fraction less than 0.50, and 2) patients with three vessel coronary artery disease and an ejection fraction less than 0.50. In both groups, coronary bypass surgery had a statistically significant beneficial effect on survival (p less than 0.05). After a decade of follow-up, the CASS randomizable patients confirm conclusions reached on the basis of the CASS randomized trial.

Alternative conduits for aortocoronary bypass grafting

The internal mammary artery is the premier conduit for initial and repeat coronary artery bypass grafting and should be used as either a pedicled or free graft whenever possible. Saphenous veins from the greater and lesser systems are distinctly second choices but can serve satisfactorily as aortocoronary grafts for many years. When neither the internal mammary arteries nor the saphenous veins are available, the cardiac surgeon today must choose from a wide variety of alternative conduits that have been used periodically over the past two decades for coronary artery bypass grafting.

Predonated autologous blood use in elective cardiac surgery

The risks of homologous blood transfusion are well documented and recently increased with the emergence of acquired immunodeficiency syndrome. Preoperative autologous donation has been suggested to reduce these risks. This is a report concerning 104 consecutive adult autologous donors (group 1) who had an elective cardiac operation. A similar group of 111 patients operated on during the same period but without autologous blood donation was used for comparison (group 2). Both groups contained similar numbers of patients with coronary artery disease, valvular disease, and mixed lesions, and both had several patients with atrial septal defects. Group 2 patients (mean age, 67.8 years) were significantly older than group 1 patients (mean age, 58.9 years) (p less than 0.05). The mean donation in group 1 was 4.1 units, but 12 (11.5%) had to discontinue donations. Increasing angina in 10 (12.2%) of the 82 patients with coronary artery disease was the most common complication, and necessitated hospitalization in two instances. In 77 (75.5%) of the 102 group 1 patients who had operation and 23 (21%) of the 110 group 2 patients, no homologous blood products were required. Group 1 patients used significantly less homologous fresh frozen plasma (0.1 unit versus 0.97 unit; p less than 0.005) and packed red blood cells (0.6 unit versus 2.1 units; p less than 0.001) than group 2 patients. Group 1 patients received 3.3 and 3.1 units of autologous packed cells and plasma, respectively. No complications of autologous transfusion were seen. Predonation of autologous blood is an effective, safe method of reducing homologous blood requirements in elective cardiac operations, but it does carry some risk, especially in patients with coronary artery disease.

Replacement of a degenerated porcine valve within a composite aortic valve graft

A simple technique for replacing a valve prosthesis within a composite aortic root graft is described. This method allows isolated valve replacement without removing the Dacron tube graft or altering the original coronary artery repair.

Risk of noncardiac operation in patients with defined coronary disease: The Coronary Artery Surgery Study (CASS) registry experience

It has been suggested that coronary artery bypass grafting (CABG) is efficacious in patients with severe coronary artery disease before they undergo a major noncardiac operation. The Coronary Artery Surgery Study (CASS) registry population was reviewed to identify variables affecting operative mortality and cardiovascular morbidity for noncardiac procedures, and to assess the influence of prior CABG on these surgical risks. Major noncardiac operations were performed on 1,600 registry patients between June 30, 1978, and June 30, 1981. Operative mortality for individuals without significant coronary artery disease (Group 1) was 0.5% (2/399) and for patients with such disease having CABG prior to a noncardiac procedure (Group 2), it was 0.9% (7/743) (Group 1 versus Group 2, p = 0.42). Patients with significant coronary artery disease undergoing noncardiac operation without prior CABG (Group 3) had an increased operative mortality, 2.4% (11/458) (p = 0.009). Group 2 patients had more severe angina symptoms (p less than 0.001) and more extensive coronary artery disease (p less than 0.001) on entering CASS than Group 3 patients. Postoperative chest pain occurred in 8.7% (40/458) of the Group 3 patients versus 4.5% (18/399) in Group 1 and 5.1% (38/743) in Group 2 (p = 0.004). No group differences were noted for the incidence of perioperative myocardial infarction or arrhythmias.(ABSTRACT TRUNCATED AT 250 WORDS)

Reoperation for coronary artery disease

Repeat coronary artery bypass grafting (CABG) accounts for approximately 5% of all myocardial revascularization procedures in the United States annually; it is estimated that nearly 7000 reoperations will be performed in 1984. Angiographic indications for repeat CABG include primary bypass graft obstruction, progressive coronary arteriosclerosis, and combined graft failure and new coronary artery disease. Saphenous vein obstruction secondary to arteriosclerosis occurs in more than half the bypass grafts at 10 years after CABG. Successful aortocoronary reoperation is dependent on careful attention to special surgical technical considerations such as chest reentry, cardiopulmonary bypass management and myocardial preservation, primary graft handling and identification of the target coronary vessel, choice of available bypass conduits, completeness of revascularization, and hemostasis and blood conservation. Operative mortality for repeat CABG is approximately twice that for an initial aortocoronary bypass procedure. Overall operative morbidity is not significantly different for primary and subsequent myocardial revascularization. Five-year survival after repeat aortocoronary surgery is approximately 90% and compares favorably with survival rates after initial CABG. However, symptomatic relief of angina pectoris is not as effective after a repeat myocardial revascularization as it was after the first CABG; only half the patients are angina-free 5 years after reoperation. As with primary revascularization, long-term graft patency rates after coronary reoperation are superior for the internal artery as compared with the saphenous vein.

Surgical survival in the Coronary Artery Surgery Study (CASS) registry

The overall surgical survival data in the Coronary Artery Surgery Study (CASS) registry have not been published to date, pending the report of the randomized medical-surgical comparison (CASS randomized trial). Non-randomized surgical survival data from the CASS registry are given in this article. The overall medical survival data from the registry were reported previously as a natural history study. There were 8,991 patients in the registry portion of CASS who had primary isolated coronary artery bypass grafting and 8,971 with follow-up of more than 30 days. The 5-year survival for all 8,971 patients was 90%, and the operative mortality was 2.37%. Patients with left main coronary artery disease had an operative mortality of 3.84% and a 5-year survival of 85%, while patients with lesions in other vessels had an operative mortality of 2.12% and a 5-year survival of 91%. Among patients without left main coronary disease, the 5-year survival was 93% in those with single-vessel and 92% in those with double-vessel disease (operative mortality was 1.50% and 1.92%, respectively) and 88% in patients with triple-vessel disease (operative mortality was 2.62%; p = 0.009). When results for patients with left main coronary artery obstruction were compared with those for triple-vessel disease, the 5-year survival figures were 85% and 88%, respectively (p = 0.02) and the operative mortality, 3.84% and 2.62%, respectively (p = 0.03). Patients with normal or nearly normal left ventricular (LV) function (i.e., LV segmental wall motion scores ranging from 5 through 11) had a 5-year survival of 92% and an operative mortality of 1.97%. Patients with moderate impairment (LV score range, 12 through 16) had a 5-year survival of 80% and an operative mortality of 4.21%. In those with poor ventricular function (LV score of 17 or greater), the 5-year survival was 65% and the operative mortality was 6.21%. The difference in survival among the three groups was significant (p less than 0.0001). Of 29 variables used in a stepwise Cox regression analysis, LV wall motion score, congestive heart failure score, age, number of operable vessels, smoking history, LV end-diastolic pressure, and percent of left main coronary artery stenosis were found to have a significant effect on long-term survival (excluding 30-day mortality), and these variables plus surgical priority and height influenced surgical mortality. When height was used in the Cox proportional hazards model, female sex was no longer a significant variable.

Survival following coronary artery bypass grafting in patients with severe angina pectoris (CASS). An observational study

This observational study evaluates the effects of the severity of angina pectoris and the treatment method upon the survival of 4,209 patients in the Coronary Artery Surgery Study registry. In this nonrandomized study, these patients met the criteria used in the Coronary Artery Surgery Study randomized trial, except for the degree of angina pectoris and the method of selection of treatment. The 5 year survival rate was greater than or equal to 93% in patients with Class I and II angina pectoris and normal left ventricular function, regardless of the number of involved vessels or treatment received. Late survival of surgically treated patients with Class III and IV angina pectoris and normal left ventricular function was similar, regardless of the number of vessels involved (greater than or equal to 92% at 5 years). Nonoperatively treated patients with Class III and IV angina pectoris and normal left ventricular function had poorer 5 year survival rates, lowest (74%) in patients with three vessel disease (p less than 0.0001). This difference was also observed in patients with abnormal left ventricular function, three vessel disease, and Class III and IV angina pectoris; the 5 year survival rates were 82% for the operative group and 52% for the nonoperative group (p less than 0.0001). These data confirm the importance of clinical as well as anatomic factors in determining the prognosis of patients with ischemic heart disease and indicate that coronary artery bypass grafting can improve late survival in patients with triple vessel disease and severe angina pectoris.

Comparison of operative mortality and morbidity for initial and repeat coronary artery bypass grafting: The Coronary Artery Surgery Study (CASS) registry experience

The National Heart, Lung, and Blood Institute's Coronary Artery Surgery Study (CASS) registry population was reviewed to allow comparison of operative mortality and morbidity rates for initial and repeat coronary artery bypass grafting (CABG) procedures. Standardized data collection was employed in CASS during patient entry (July 1, 1974, to May 31, 1979) and follow-up (ended November 30, 1982). Initial CABG was performed on 9,369 patients. Mean follow-up was 60.5 months. Repeat CABG was required in 283 patients (3.0%). The mean interval between operations was 39.3 months. Individuals needing reoperation tended to be young (p less than 0.0001) and female (p less than 0.002) and to have less extensive coronary artery disease (p less than or equal to 0.0001), less left ventricular impairment (p less than 0.0001), less evidence of congestive heart failure (p = 0.006), and fewer coronary vessel systems bypassed at the first operation (p less than 0.0001). Repeat CABG carried an increased risk of death compared with initial CABG (5.3% versus 3.1%, respectively; p less than 0.05). However, the rates of perioperative myocardial infarction (6.4% for repeat and 5.8% for initial CABG) and of all surgical complications combined (30.6% versus 27.9%) were not significantly different from those at initial CABG.

Reoperation for aortic coarctation

Reoperation for aortic coarctation has become common because of several factors: (1) increased physician awareness that hypertensive cardiovascular disease continues to threaten the prognosis of the patient following coarctectomy and that investigation in some symptomatic individuals after coarctectomy will demonstrate a residual or recurrent coarctation, even many years after the primary repair; (2) the widespread application of stress testing, which can reveal marked arm-to-leg pressure gradients not observed at rest, to the routine postcoarctectomy follow-up examination; (3) improved noninvasive aortic evaluation techniques, such as ultrasound; and (4) higher salvage rates among infants undergoing urgent coarctation repairs and the recognition that these children subsequently are at high risk for recoarctation. A surgical decision-making process characterized by flexibility provides maximum patient safety; no single reoperation technique can be applied in all situations. Individual circumstances may dictate recoarctation repair by resection with end-to-end anastomosis, tube graft interposition, aortoplasty, or tube graft bypass. The need for a temporary aortic shunt or partial left atriofemoral bypass to maintain adequate distal aortic perfusion pressure during the repair means that these methods must be available at all reoperations. Diligent efforts to repair all hemodynamically significant residual and recurrent coarctations are necessary if the natural fate of premature death is to be avoided for patients with these lesions.

Potential for percutaneous transluminal coronary angioplasty before initial and repeat coronary artery bypass grafting in the Coronary Artery Surgery Study (CASS) Registry population

Retrospective analysis of preoperative angiograms was conducted to determine potential candidacy for PTCA among the NHLBI Coronary Artery Surgery Study (CASS) Registry population undergoing initial and repeat CABG. Conservative criteria believed to be universally acceptable for PTCA were used. Patients were considered potential PTCA candidates if: (1) CABG had been performed to only 1 coronary artery system; (2) the critical disease was localized to the most proximal segment of that coronary artery system; (3) all distal segments of that coronary artery system were free of critical disease; and (4) the morphologic characteristics of the obstructing lesion were discrete and isolated. Left main CAD was excluded. Among persons who underwent initial CABG, 2.8% (261 of 9,369) were PTCA candidates, and 7.1% (20 of 283) of those who underwent repeat CABG were considered suitable for PTCA. The operative mortality risk of the PTCA candidates who underwent initial CABG was 0.4% (1 of 261). No PTCA candidates died during repeat CABG. Perioperative MI occurred in 2.3% (6 of 261) of the PTCA candidates who had initial CABG; none occurred among those who underwent repeat surgery. Total surgical complications occurred in 15.7% (41 of 261) of the PTCA candidates at initial CABG and in 5% (1 of 20) who had repeat CABG. These operative mortality and morbidity risks are lower than those reported for similar patients who undergo PTCA.

Cardiac rhabdomyoma in the neonate: surgical management

Rhabdomyoma is the most common cardiac neoplasm in neonates. Tuberous sclerosis is found in half of the patients with rhabdomyomas. We maintain a surgical policy of accepting for operation only neonates in whom it has been demonstrated that the primary cause for hemodynamic compromise is obstructing, intracavitary neoplasms. Only the intracavitary portions of the rhabdomyoma are excised; no effort is made to completely remove all intramural tumors. Rhabdomyomas demonstrate benign pathological characteristics and may regress. Neonates with rhabdomyomas but no hemodynamic impairment, or those in whom only intramural masses can be demonstrated, are not considered surgical candidates. Tuberous sclerosis by itself should not be judged a contraindication to operation. The results of our surgical policy regarding rhabdomyomas in neonates are reported in two case presentations.

Preservation of the myocardium during coronary artery bypass grafting

The influence of three methods of myocardial preservation used during coronary artery bypass grafting on operative mortality and perioperative myocardial infarction was evaluated in seven institutions participating in the Coronary Artery Surgery Study (CASS). Both operative mortality and perioperative infarctions were comparable with either normothermic and topical hypothermic myocardial preservation. The addition of potassium cardioplegia to hypothermia lowered both operative mortality and perioperative myocardial infarction (p less than 0.01 and p less than 0.001, respectively). Stepwise multivariate discriminant analysis revealed that the high-risk clinical and angiographic variables were the most important determinants of operative mortality, followed by surgical priority and the use of potassium cardioplegia. However, none of the clinical, angiographic and surgical variables other than the use of potassium cardioplegia influenced the incidence of perioperative myocardial infarction.

Anomalous right subclavian artery arising proximal to a postductal thoracic aortic coarctation

Approximately 1% of patients with postductal thoracic aortic coarctation have an associated anomalous right subclavian artery. Previous reports indicated that the aberrant right subclavian vessel arose distal to the coarctation site. The case of a patient is presented in whom the anomalous right subclavian artery originated proximal to the postductal coarctation. We believe this to be among the first reports of this entity. The embryological development pathway and clinical implications of this congenital defect complex are discussed.