The nature of treatment selection in coronary artery disease. Experience with medical and surgical treatment of a chronic disease

Implementation of a computerized cardiovascular information system in a private hospital setting

BACKGROUND

The use of clinical databases improves quality of care, reduces operating costs, helps secure managed care contracts, and assists in clinical research. Because of the large physician input required to maintain these systems, private institutions have often found them difficult to implement. At LDS Hospital in Salt Lake City, Utah, we developed a cardiovascular information system (LDS-CIS) patterned after the Duke University Cardiovascular Database and designed for ease of use in a private hospital setting.

METHODS

Features of the LDS-CIS include concise single-page report forms, a relational database engine that is easily queried, automatic generation of final procedure reports, and merging of all data with the hospital's existing information system. So far, data from more than 14,000 patients have been entered.

RESULTS

LDS-CIS provides access to data for research to improve patient care. For example, by using data generated by LDS-CIS, the policy requiring surgical backup during percutaneous transluminal coronary angioplasty was eliminated, resulting in no increased patient risk while saving nearly $1 million in 1 year. LDS-CIS generates physician feedback reports documenting performance compared with peers. This physician self-evaluation has standardized and improved care. Information from LDS-CIS has been instrumental in securing and maintaining managed care contracts. LDS-CIS risk analysis provides physicians with outcomes data specific to their current patient's demographics and level of disease to assist in point of care decisions.

CONCLUSION

The use of LDS-CIS in the routine operations of LDS Hospital heart services has been found to be feasible, beneficial, and cost-effective.

Coronary artery surgery in the elderly: long-term follow-up

BACKGROUND

There has been controversy concerning the indications for coronary artery surgery in the elderly, particularly in countries where health resources are restricted.

AIMS

To assess the results of coronary artery bypass grafting (CABG) in a large group of elderly subjects with regard to initial risks and long term follow-up.

METHODS

Ninety-six consecutive patients aged 70 years or older underwent isolated CABG between January 1981 and December 1985. Long term follow-up was obtained in 94 (98%).

RESULTS

The mean age was 71.6 years (70-78) and mean duration of follow-up 73 months. Seventy (73%) were male. In 80 cases the myocardial score was > 10. In 22 of 90 who had left ventricular angiography the ejection fraction was < 50%. Hospital survival was 96% and the five year survival 77%. It was not influenced by gender, myocardial score, ejection fraction or age at the time of operation. The status of survivors was reviewed in 1991. Of the 55 long term survivors 35 (64%) were free of angina. Eight (15%) and ten (18%) were in the Canadian Cardiovascular Society Angina classes 1 and 2 respectively. Seventeen patients (31%) had symptoms of heart failure with 14 (25%) in NYHA class 2 and 3 (5%) in class 3. Eight patients (15%) had survived a cerebrovascular event during follow-up. There were 35 late deaths (37%). Sixteen of these were cardiac, 18 due to other causes and one unknown.

A critical perspective on coronary artery disease and coronary bypass surgery

This paper examines coronary artery disease and coronary artery bypass graft (CABG) surgery from a critical medical anthropological perspective. It explores the issue of why an expensive, individualistic, and mechanistic treatment for the symptoms of coronary artery disease (CABG surgery) has come to be so widely used to treat a condition which is so clearly related to occupational, social and environmental stresses and to behavioral factors. The paper also addresses the issue of why CABG surgery has proliferated in the absence of firm evidence from controlled studies that it is an effective long-term mode of treatment for many patients with this disease. Through this analysis of the growth and continued overuse of CABG surgery the social nature of biomedical knowledge and the socio-cultural, political and economic nature of biomedical decision making are revealed.

Assessment of coronary bypass surgery and percutaneous transluminal coronary angioplasty

Coronary bypass surgery developed as another in a line of surgical procedures dating back more than 60 years. The medical profession at first assessed this procedure with time-honored anecdotal techniques. Gradually, for a variety of reasons, improved methods of comparisons worked their way into assessments of bypass surgery. Randomized controlled trials met resistance but have been very influential. Assessment of percutaneous transluminal coronary angioplasty has benefited from the knowledge generated during the last 25 years, but clinicians have been slower to apply the most advanced techniques.

Superiority of quantitative exercise thallium-201 variables in determining long-term prognosis in ambulatory patients with chest pain: a comparison with cardiac catheterization

The purpose of this study was to determine the prognostic utility of quantitative exercise thallium-201 imaging and compare it with that of cardiac catheterization in ambulatory patients. Accordingly, long-term (4 to 9 years) follow-up was obtained in 293 patients who underwent both tests for the evaluation of chest pain: 89 had undergone coronary artery bypass graft surgery within 3 months of testing and were excluded from analysis, 119 experienced no cardiac events and 91 had an event (death in 20, nonfatal myocardial infarction in 21 and coronary artery bypass operations performed greater than 3 months after cardiac catheterization in 50). When all variables were analyzed using Cox regression analysis, the quantitatively assessed lung/heart ratio of thallium-201 activity was the most important predictor of a future cardiac event (chi 2 = 40.21). Other significant predictors were the number of diseased vessels (chi 2 = 17.11), patient gender (chi 2 = 9.43) and change in heart rate from rest to exercise (chi 2 = 4.19). Whereas the number of diseased vessels was an important independent predictor of cardiac events, it did not add significantly to the overall ability of the exercise thallium-201 test to predict events. Furthermore, information obtained from thallium-201 imaging alone was marginally superior to that obtained from cardiac catheterization alone (p = 0.04) and significantly superior to that obtained from exercise testing alone (p = 0.02) in determining the occurrence of events. In addition, unlike the exercise thallium-201 test, which could predict the occurrence of all categories of events, catheterization data were not able to predict the occurrence of nonfatal myocardial infarction. The exclusion of bypass surgery and previous myocardial infarction did not alter the results. In conclusion, data from this study demonstrate that exercise thallium-201 imaging may be superior to data from both exercise testing alone and cardiac catheterization data alone for predicting future events in ambulatory patients who have undergone both exercise thallium-201 imaging and catheterization for the evaluation of chest pain.

Quantification of myocardium at risk in unstable angina: comparison of patients with and without previous infarction

We studied two subgroups of patients with unstable angina pectoris: 35 without (Group A) and 73 with (Group B) previous myocardial infarction. The severity of coronary artery disease was assessed by means of a previously described scoring system. This scoring system was used to calculate the proportion of left ventricular myocardium fed by significantly (greater than 75% luminal area reduction) stenosed coronary arteries (called percent myocardium threatened). To estimate the amount of myocardium lost by previous infarction we used a four-point wall motion score for each of seven left ventricular wall segments: a value of 2 was given to normokinetic segments, 1 for hypokinetic segments, 0 for akinetic and -1 for dyskinetic segments. The deficit in wall motion score was used to estimate the amount of myocardium infarcted. This was then subtracted from the proportion of myocardium threatened to yield the proportion of myocardium still in jeopardy. We found a different extent and severity of coronary artery disease between the two subgroups. In the group without previous infarction, the numbers of patients with one-, two- and three-vessel disease were 15, 9, and 11, respectively (or 43, 26, and 31%). In those with a previous infarction, the respective numbers were 11, 23, and 39 (or 15, 31.5, and 53.5%). This difference is statistically significant (P less than 0.01). The mean number of stenotic arteries was 1.9 +/- 0.9 in the patients without previous infarction and 2.4 +/- 0.7 in those with an infarction (P less than 0.05). Using the above-mentioned scoring system the score was 3.2 +/- 1.4 in patients without previous infarction and 4.0 +/- 1.6 in those with previous infarction (P less than 0.05). The percent myocardium threatened was 53.6 +/- 24.1 vs. 68.7 +/- 24.7 (P less than 0.01). Wall motion score was 13.8 +/- 0.6 in Group A and 10.6 +/- 3.1 in Group B (P less than 0.01), which gives values for the proportion of myocardium infarcted of 1.6 +/- 4.2 and 24.2 +/- 22.0%, respectively. The percentage still in jeopardy (after subtracting that infarcted from that threatened) was 51.8 +/- 22.7 in those without and 44.2 +/- 31.1 in those with a previous infarction: this difference is not statistically significant. We conclude that patients with unstable angina pectoris who have sustained a previous myocardial infarction have more severe coronary artery disease than similar patients without previous infarction. The amount of left ventricular myocardium still in jeopardy of becoming infarcted is, however, the same.

Ischemic cardiomyopathy

The term "ischemic cardiomyopathy" was used initially to describe a clinical syndrome that was indistinguishable from primary congestive cardiomyopathy but due to severe, diffuse coronary artery disease. The term has been expanded to include the larger category of myocardial disease secondary to coronary artery disease. Using this expanded definition, we have discussed the varied clinical presentations of congestive ischemic cardiomyopathy and restrictive ischemic cardiomyopathy (stiff heart syndrome and right ventricular infarction), and how the effects of ischemia on left ventricular systolic and diastolic performance may cause these varied presentations. The prognosis of any ischemic cardiomyopathy is related primarily to the degree of ventricular dysfunction and the extent of coronary artery disease. Therapy is aimed at preventing or ameliorating myocardial ischemia and halting the progression of, or even reversing, the deterioration in myocardial function.

Natural history of severe left ventricular dysfunction after myocardial infarction

The prevalence and prognosis of severe left ventricular dysfunction after infarction was prospectively analyzed in a series of 259 male patients aged 60 years or less surviving an acute myocardial infarction. All patients underwent coronary angiography 30 days after the acute event and were followed up for a mean period of 34 months (range, 15 to 55 months). Forty-five patients (17 percent) were found to have severe left ventricular dysfunction (ejection fraction less than or equal to 30 percent). Comparison of patients with and without severe impairment of left ventricular function showed the former to have a lower cardiac index (p less than 0.001), higher left ventricular end-diastolic volume index (p less than 0.001), and a higher prevalence of three-vessel disease (p less than 0.025) and of total or subtotal occlusion of at least one coronary artery (p less than 0.025). While the occurrence of congestive heart failure was higher in patients with severe left ventricular dysfunction (p less than 0.001), the probability of developing angina was similar in both groups. Cox's regression analysis showed ejection fraction to be the only independent predictor of survival in patients with severe impairment of left ventricular function. An ejection fraction of 20 percent or less identified a subset of patients with the highest mortality (62 percent at four years), significantly different from that of patients whose ejection fraction was between 21 and 30 percent (28 percent) (p less than 0.001).

Fifteen year survival study of patients with obstructive coronary artery disease

Survival rates were determined for a group of 598 patients in whom severe coronary disease was demonstrated by arteriography; initially they were treated medically and were followed-up for 15 years. Deaths due to noncoronary causes were uncommon (5% of total) in the first 5 year period but were frequent (36%) in the third period. Survival rates were 48%, 28%, 18%, and 9% for patients with single-, double-, triple-, and left main artery disease, respectively. Abnormalities documented by ventriculography were related to survival. In 386 patients who would have been candidates for bypass surgery, survival rates were 58%, 35%, 26%, and 11% for those with single-, double-, triple-, and left main artery disease, respectively. Cardiac survival curves for single-, double-, and triple-artery disease in candidates for surgery and curves constructed on the basis of 3% mortality per artery per year corresponded fairly closely. When an abnormal electrocardiogram (ECG) is considered as a single variable in multivariate analysis, 5 year survival rates of candidates for surgery were influenced by the following in order of importance: abnormal ECG, symptoms at least 5 years in duration, triple-artery disease, double-artery disease, and arteriosclerosis obliterans. A simple prognostic stratification was devised that used only ECGs and duration of symptoms for each subset based on the number of arteries affected.

Reoperation after aortocoronary bypass procedure. Results in 53 patients in a group of 1041 with consecutive first operations

Of 1041 patients with consecutive aortocoronary bypass operations, 53 (5.1%) underwent reoperation during a mean follow-up time of three and a half years. The operative mortality of first operations was 1.2%, and of reoperations 3.8%. The anatomical reason for reoperation was failure of the bypass graft in 41 (77%) patients, which in 18 was accompanied by progression of disease. Progression alone was seen in seven (13%). When symptoms occurred within six months after the first operation, failure of the bypass graft(s) was nearly always found--in 32 out of 36 instances. Progression in non-bypassed arteries was seen only when symptoms occurred later. Late results in angina pectoris were less favourable in the group undergoing reoperation: 31 (65%) of the 48 operated on twice and 406 (46%) of the 877 patients operated on once still had angina at late follow-up. The same fraction in both groups was improved by operation: 88% versus 89%.

Outcome in one-vessel coronary artery disease

We analyzed the clinical outcomes in 688 patients with isolated stenosis of one major coronary artery. The survival rate among patients with disease of the right coronary artery (RCA) was higher than that among patients with left anterior descending (LAD) or left circumflex coronary artery (LCA) disease. The survival rate among patients in all three anatomic subgroups exceeded 90% at 5 years. The presence of a lesion proximal to the first septal perforator of the LAD was associated with decreased survival compared with the presence of a more distal lesion. For the entire group of one-vessel disease patients, total ischemic events (death and nonfatal infarction) occurred at similar rates regardless of the anatomic location of the lesion. Left ventricular ejection fraction was the baseline descriptor most strongly associated with survival, and the characteristics of the angina had the strongest relationship with nonfatal myocardial infarction. No differences in survival or total cardiac event rates were found with surgical or nonsurgical therapy. The relief of angina was superior with surgical therapy, although the majority of nonsurgically treated patients had significant relief of angina. The survival rate of patients with one-vessel coronary disease is excellent, and the risk of nonfatal infarction is low. Clinical strategies for the care of these patients must consider the long-term clinical course of one-vessel coronary disease.

Prognosis of asymptomatic or mildly symptomatic patients with coronary artery disease

One hundred forty-seven asymptomatic or mildly symptomatic patients with coronary artery disease, who did not have significant left main coronary occlusion and had an ejection fraction greater than 20 percent, were followed up prospectively for 6 to 67 months (average 25). Significant obstruction of one coronary artery was present in 28 percent of patients, of two coronary arteries in 31 percent and of three coronary arteries in 41 percent. Ejection fraction was 55 percent or greater in 69 percent of patients. During the follow-up there were eight deaths (annual mortality rate 3 percent for the entire group, 1.5 percent for patients with single and double vessel disease but 6 percent for those with triple vessel disease). Better definition of high and low risk subgroups of patients with three vessel disease was accomplished with exercise testing. Despite a history of mild symptoms, 25 percent of the patients with triple vessel disease exhibited poor exercise capacity on exercise testing after administration of beta adrenoceptor blocking agents and nitrates was discontinued; of these, 40 percent either died (20 percent) or had progressive symptoms requiring operation (20 percent) (annual mortality rate 9 percent). Of the patients with good exercise capacity, only 22 percent either died (7 percent) or had progressive symptoms (15 percent) (annual mortality rate 4 percent). Thus, prognosis is excellent in patients with no or mild symptoms who have one or two vessel coronary disease. Patients with three vessel disease who have good exercise capacity documented by objective testing have an annual mortality rate of 4 percent. However, because patients with three vessel disease and poor exercise capacity have an extremely grave prognosis, it would appear reasonable to recommend coronary bypass surgery for this subgroup, even in the absence of supporting data derived from a definitive randomized study.

Determinants of foster care placement for the maltreated child

This study examined the records of the North Carolina Central Registry of Child Abuse and Neglect to determine which social, family, and child characteristics were most influential in the decision to place a child in foster care. These records contained all theoretically relevant factors as well as demographic data. Analysis included the computation of odds ratios for foster care for each of 250 variables. A maximum likelihood logistic regression model was constructed to obtain the independent and cumulative contribution of each factor. Some expected variables such as parental stress factors (substance abuse) and types of abuse (burns and scalds) placed a child at a significant risk for placement in foster care (p less than 0.01). However, less obvious factors such as referral source (law enforcement agencies) or geographic area also placed children at risk. Overall, the model explained little of the variance of these decisions (R2 = 0.168) and poorly predicted placement (sensitivity 66.3 per cent, specificity 74.6 per cent). Using existing data, we were unable to adequately describe the decision process in selecting foster care.

Determinants of foster care placement for the maltreated child

This study examined the records of the North Carolina Central Registry of Child Abuse and Neglect to determine which social, family, and child characteristics were most influential in the decision to place a child in foster care. These records contained all theoretically relevant factors as well as demographic data. Analysis included the computation of odds ratios for foster care for each of 250 variables. A maximum likelihood logistic regression model was constructed to obtain the independent and cumulative contribution of each factor. Some expected variables such as parental stress factors (substance abuse) and types of abuse (burns and scalds) placed a child at a significant risk for placement in foster care (p less than 0.01). However, less obvious factors such as referral source (law enforcement agencies) or geographic area also placed children at risk. Overall, the model explained little of the variance of these decisions (R2 = 0.168) and poorly predicted placement (sensitivity 66.3 per cent, specificity 74.6 per cent). Using existing data, we were unable to adequately describe the decision process in selecting foster care.

Long-term survival after coronary bypass surgery. Comparison of various subsets of patients with general population

Life-table analysis consecutive cases of isolated coronary bypass surgery at the Buffalo Hospital between 1973 and 1977 showed an estimated survival of 94 per cent at five years, equal to that of an age- and sex-matched group of the US population. Subsets of these patients divided according to sex, age, number of vessels narrowed, number of segments grafted, history of myocardial infarction, ejection fraction, and presence of unstable angina have estimated survivals not statistically less in any of these subsets than that of matched cohorts of the general population.

Clinical and angiographic predictors of operative mortality from the collaborative study in coronary artery surgery (CASS)

Fifteen institutions participating in the Collaborative Study in Coronary Artery Surgery (CASS) have performed isolated coronary artery bypass surgery upon 6630 patients (1061 women and 5569 men) for coronary artery disease. The overall operative mortality (OM) was 2.3% (range 0.3-6.4%). Mortality increased with age, from 0 in the group 20-29 years old to 7.9% in the group 70 years and older. OM was higher for women in each group, ranging from 2.8% for ages 30-39 years to 12.3% for age 70 years and older (0.8% and 5.8% for men). Clinical manifestations of congestive heart failure were associated with increased OM. Mortality was 1.4% in one-vessel, 2.1% in two-vessel and 2.8% in three-vessel disease (diameter narrowing greater than or equal to 70%). Among 1019 patients with left main coronary artery (LMCA) stenosis, OM ranged from 1.6% in patients with mild stenosis and a right-dominant system to 25% in patients with severe (greater than or equal to 90%) stenosis and left dominance. OM varied with ejection fraction (EF) (1.9% for EF greater than or equal to 50% to 6.7% for EF less than 19%) and left ventricular wall motion score (1.7% for least abnormal to 9.1% for most abnormal). For elective surgery, OM was 1.7%, for urgent surgery 3.5%, and for emergency surgery 10.8%. Mortality was 40.0% among 30 patients with severe LMCA stenosis who underwent emergency revascularization. Advanced age, female sex, symptoms of heart failure, LMCA stenosis, impaired left ventricular function and nonelective surgery are associated with a higher OM. These factors should be considered in the selection of patients for coronary artery surgery.

Comparisons of the effects on survival after coronary artery surgery in subgroups of patients from the Seattle Heart Watch

We compared the survival of medically and surgically treated coronary artery disease patients in subgroups of patients to determine those most or least likely to benefit from surgery after an average of 5.5 years of follow-up. Cox's regression model for survival analysis was used in conjunction with data from all patients to estimate and test for the significance of the effects of surgery on survival in subgroups of patients, defined by one or more of the following variables: number of stenotic vessels (greater than or equal to 70%), ejection fraction, age, heart murmur, diuretic therapy, ventricular arrhythmia on resting ECG, left main coronary artery stenosis greater than or equal to 50%, previous myocardial infarction, cardiomegaly, congestive heart failure, unstable angina, and functional class. The Cox model adjusts for differences between medical and surgical patients in variables shown to be predictive of survival. A statistically beneficial effect of surgery on survival was seen in patients with two- or three-vessel disease, ejection fraction greater than or equal to 30%, age greater than or equal to 48 years, no heart murmur, no diuretic therapy, no ventricular arrhythmia on resting ECG, left main coronary artery stenosis less than 50%, no cardiomegaly, and no congestive heart failure. The converse subgroups defined by these variables did not show a significant beneficial effect from surgery. However, patient subgroups defined by presence or absence of prior myocardial infarction or unstable angina and New York Heart Association functional class I-II vs III-IV all showed beneficial effects from surgery.

Prognostic importance of anginal symptoms in angiographically defined coronary artery disease

To evaluate the prognostic importance of anginal symptoms, 44 patients with angiographically defined coronary artery disease and no anginal symptoms at time of cardiac catheterization were selected from the Duke Harvard Collaborative Data Bank. They were "matched" with 127 symptomatic patients in the Data Bank who had similar coronary anatomy and ventricular function. Follow-up data indicated that the patients without anginal symptoms had a significantly better prognosis over a 7 year period than did those with symptoms: Annual mortality in the asymptomatic group was 2.7 percent compared with 5.4 percent in the group with angina (P 0.05). Although the patient population was a highly selective one and the matching categories were relatively broad, these results suggest that the presence of anginal symptoms may be an important independent correlate of prognosis in patients with coronary artery disease. The absence of angina did not preclude the presence of multivessel disease and did not necessarily imply a benign prognosis, because the yearly mortality rate was nearly 5 percent in the subgroup of asymptomatic patients with three vessel disease.

Outcome in medically treated coronary artery disease. Ischemic events: nonfatal infarction and death

In this study we extended the characterization of outcome in 1214 medically treated patients with coronary disease by considering nonfatal infarction and death together as ischemic events. At 7 years, the cumulative event rate was 47% (18% for nonfatal infarction as the initial event and 29% for death as the initial event). In multivariable analysis of 81 baseline descriptors, 11 (six clinical and five catheterization) were independent predictors of events. Progressive chest pain, number of diseased vessels, left main stenosis and left ventricular (LV) function were the most important predictors. Progrressive pain was a more important predictor of total events than of survival alone. In patients with one-, two- or three-vessel disease and normal LV function, nonfatal infarcation accounted for at least 50% of initial events. In patients with left main disease or severe LV dysfunction, death was the predominant event. These results have important implications for interpreting the natural history of coronary artery disease.

Clinical and arteriographic variables predictive of survival in coronary artery disease

Survival, subsequent myocardial infarction and current anginal status were determined for 90 nearly consecutive patients who underwent coronary arteriography at the Johns Hopkins Hospital between 1960 and 1967. All patients had at least one coronary arterial narrowing equal to or greater than 70 percent; 78 of 90 patients would be candidates for coronary bypass surgery by present criteria. Twenty-nine of the 78 surgically "suitable" patients died of cardiac causes; 7 of 49 survivors sustained an acute myocardial infarction (mean follow-up period 9.9 years). Patients with a 70 percent or greater narrowing proximal to the first septal branch of the left anterior descending coronary artery had a significantly greater mortality compared with patients with equivalent narrowing distal to the first septal branch or with patients without 70 percent or greater narrowing of the left anterior descending artery. The patients with a 70 percent or greater narrowing of the left anterior descending artery who died were those with a significant narrowing in at least one other major coronary artery. Multivariate stepwise discriminate function analysis of all clinical, electrocardiographic (except stress electrocardiographic) and arteriographic variables identified three independent predictors of mortality: (1) the simultaneous occurrence of a narrowing in left anterior descending and right coronary arteries, (2) prior myocardial infarction; and (3) 70 percent or greater narrowing proximal to the first anterior descending septal branch. When stress electrocardiographic findings were included, a "positive" stress electrocardiographic test was also an independent predictor of mortality.

Clinical judgment and statistics. Lessons from a simulated randomized trial in coronary artery disease

A simulated randomized clinical trial in coronary artery disease was conducted to illustrate the need for clinical judgment and modern statistical methods in assessing therapeutic claims in studies of complex diseases. Clinicians should be aware of problems that occur when a patient sample is subdivided and treatment effects are assessed within multiple prognostic categories. In this example, 1073 consecutive, medically treated coronary artery disease patients from the Duke University data bank were randomized into two groups. The groups were reasonably comparable and, as expected, there was no overall difference in survival. In a subgroup of 397 patients characterized by three-vessel disease and an abnormal left ventricular contraction, however, survival of group 1 patients was significantly different from that of group 2 patients. Multivariable adjustment procedures revealed that the difference resulted from the combined effect of small imbalances in the distribution of several prognostic factors. Another subgroup was identified in which a significant survival difference was not explained by multivariable methods. These are not unlikely examples in trials of a complex disease. Clinicians must exercise careful judgment in attributing such results to an efficacious therapy, as they may be due to chance or to inadequate baseline comparability of the groups.

Occlusive disease confined to the right coronary artery: clinical features, surgical treatment and long-term follow-up in 124 patients

The clinical presentation and surgical results in 124 consecutive patients who underwent aorta to right coronary arterial bypass surgery from January 1970 through June 1977 were reviewed. Preoperatively, 75 percent of the patients were in New York Heart Association functional class III or IV, 9 percent presented with unstable angina and 5 percent had life-threatening ventricular arrhythmias. All patients had high grade occlusive disease confined to the right coronary artery; 34 percent of the patients had associated nonsignificant disease (less than 50 percent intraluminal narrowing) of the left anterior descending or circumflex artery. Left ventricular function was normal in 63 percent and minimally impaired in 37 percent. The operative mortality rate was 1.6 percent. The course of the 122 survivors was followed up for 3.7 years. There were four late deaths, and the 5 year mortality rate was 4.0 percent. Eight patients were reoperated on because of recurrence of symptoms and occlusion of the graft or progression of occlusive disease of the other major coronary arteries, or both. Of the remaining 110 patients, 98 are either in functional class I or II, 60 are taking no cardiovascular medications, 52 are working full time without angina nad 73 are asymptomatic. In summary, bypass surgery for isolated right coronary artery disease has a low mortality rate and results in excellent long-term symptomatic improvement.

Aortocoronary bypass grafting in the management of patients with coronary artery disease

There is widespread agreement that aortocoronary bypass grafting generally lessens the symptoms and functional limitations of patients with angina pectoris. Evidence for prolongation of life or prevention of myocardial infarction, arrhythmias and ventricular dysfunction is inconclusive. Harmful effects associated with surgical management of coronary artery disease can be documented in terms of operative mortality, perioperative myocardial infarction, graft occlusion and progression of occlusive disease in the native circulation. In this review of published experience, the accomplishments and the limitations of myocardial revascularization are considered in various clinical settings. Critical assessment of evolving information leads to the conclusion that widespread application of this procedure beyond the alleviation of symptoms refractory to medical therapy is not justified by present data.

Evidence from a nonrandomized study that coronary surgery prolongs survival in patients with two-vessel coronary disease

Within the larger Seattle Heart Watch arteriography registry, surgically treated patients non randomly selected for direct myocardial revascularization were matched to medically treated patients such that each of the 287 pairs was identical in seven variables (ejection fraction, ventricular arrhythmia on resting electrocardiogram, age, heart murmur, stenosis of left main coronary artery greater than or equal to 50%, number of vessels with stenosis greater than or equal to 70%, and use of diuretics) previously demonstrated to be independently predictive of survival. Actuarial survival analyses based on cardiovascular deaths (average follow-up 3.5 years) indicate improved survival for the entire surgical matched pair cohort (p = 0.008) and for the surgically treated subgroup with two-vessel disease (p = 0.0002) when compared to the medical cohort. These results were confirmed by examination of the entire arteriography registry (n = 1524) in which these seven variables were known, using Cox's model for survival analysis. This multivariate, statistical technique indicated that the surgical mode of therapy was significantly predictive of improved survival in surgically treated patients for the entire registry (p = 0.008) and for the subgroup with two-vessel disease (p = 0.0005).

Coronary bypass for stable angina: a prospective randomized study

To evaluate the effects of coronary-artery bypass, 100 patients with stable, disabling angina were randomized to medical (49) or surgical (51) therapy. There was no statistical difference in major cardiac events after three years (death in five medical vs. four surgical, infarction in eight vs. 10, and unstable angina requiring operation or reoperation in eight vs. three cases). Surgical patients with three-vessel disease had fewer major events (P less than 0.05) than the comparable medical group and less unstable angina requiring operation (P less than 0.02). All unstable angina was less frequent in the surgical group (15 vs. six, P less than 0.01). Functional classification improved more in surgical patients at six months (P less than 0.01) and at late followup examination (P less than 0.05). After six months, surgical patients achieved significantly higher exercise work loads (P less than 0.01), exercise heart rates (P less than 0.05), maximum paced heart rates (P less than 0.01) and myocardial lactate extraction (P less than 0.01). On the basis of this interim report of a relatively small group of patients, we conclude that bypass results in greater functional improvement and less unstable angina than medical therapy. The likelihood of death and myocardial infarction is unchanged by operation.

Results of aortocoronary bypass operations. Follow-up in 343 patients

Three hundred and forty-three patients who had aortocoronary bypass graft operations for disabling angina were followed up for from 6 months to 5 years (average 2 years). 80 per cent had multiple grafts and 20 per cent had additional endarterectomy. The overall mortality within one month of operation was 5 per cent, and in those who had vein graft procedures only was 4 per cent. 11 per cent had a postoperative myocardial infarction (6% perioperative) and there were 3 per cent late deaths. At 3 years 90 per cent are surviving. 80 per cent are asymptomatic without treatment. The mean angina grade was 0.3 at the latest follow-up, compared with 2.5 before operation; maximum exercise tolerance was also significantly improved (P less than 0.001). When angina recurred, it did so in 80 per cent of the cases within 12 months of operation and was usually attributable to inadequate revascularisation. Ventricular function as assessed by preoperative ventriculography was the factor most clearly related to survival rate and the early excellent results of coronary bypass operations seem to be maintained up to 5 years. It is, therefore, reasonable to continue to advise operation if only for relief of angina.

Results of aortocoronary bypass grafting in patients with subendocardial infarction: late follow-up

Twenty-eight patients with subendocardial infarction (Group A) were compared with 28 patients with unstable angina (Group B) and 28 with stable angina (Group C) matched for age and sex. The three groups did not differ in prevalence of diabetes, hypertension, old infarction or duration of disease. There were no significant differences in number of diseased vessels, coronary score, abnormal left ventricular wall motion or left ventricular end-diastolic pressure. Angiograms performed 2 weeks postoperatively revealed closure of 3 of 31 grafts (16 patients) in Group A, closure of 3 of 34 grafts (17 patients) in Group B and closure of 6 of 50 grafts (22 patients) in Group C (differences not significant). Postoperative angiograms showed improved wall motion in 37 percent of Group A, 53 percent of Group B and 36 percent of Group C (differences not significant). Postoperative new Q waves appeared in one hospital in Group A and in two patients in Groups B and C. There were no hospital or late deaths. In a mean follow-up period of 29 months, 68 percent of patients in Group A, 61 percent in Group B and 54 percent in Group C were asymptomatic. Thus, bypass grafting was performed with similarly low mortality and morbidity in patients with subendocardial infarction and in those with angina; more than one third of postoperative angiograms in the three groups showed improved wall motion; and late follow-up studies demonstrated functional improvement in the majority of patients in all three groups.

Value of coronary bypass surgery. Controversies in cardiology: Part I

The value of coronary bypass surgery has been studied carefully during the last decade. Four methods, none perfect, have been used to compare the results of such surgery with the results of medical therapy. New data are likely to be merely supportive rather than the outcome of a definitive study with a new and a acceptable experimental design. It is therefore time to analyze the available data in light of the treacherousness of the disease and to determine if a clear trend is evident. There appears to be sufficient evidence to state that properly performed coronary bypass surgery will increase coronary blood flow and relieve angina pectoris in 90 percent of patients; total relief of angina can be expected in 60 percent and partial relief in 30 percent. Compared with modern medical therapy, properly performed coronary bypass surgery appears to prolong the life of patients who have obstruction of the left main coronary artery or triple or double vessel disease. There is not adequate evidence to state that the procedure will prolong the life of patients with single vessel obstruction. However, patients with single vessel obstruction and unacceptable angina pectoris should be considered for bypass surgery (especially patients with obstruction of the left anterior descending coronary artery). In practice, at Emory University Hospital, Atlanta, bypass surgery is recommended for young people with few symptoms if compelling obstructing lesions are present and in older patients only if their symptoms require it. Medical therapy is given before and after bypass surgery. When bypass surgery is performed in an excellent fashion (operative risk 1 percent) a great deal of "controversy" about this problem vanishes.

Natural history of obstructive coronary artery disease: ten-year study of 601 nonsurgical cases

The most important factors in the prognosis of coronary artery disease are the number of arteries severly obstructed, significant involvement of the left main coronary artery, and generalized impairment of left ventricular function or ventricular aneurysm. Other prognostic influences at least partially independent of these factors are the severity of functional impairment imposed by angina pectoris, electrocardiographic evidence of left ventricular hypertrophy or conduction defects, hypertension, and diabetes. Candidates for bypass operation have a better prognosis than noncandidates, but difference in left ventricular function is responsible. Refinement of prognostic precision will depend largely on future improvement in measurement of obstructive disease and left ventricular function serially and better knowledge of the cause or causes of coronary artery disease.

Prediction of multivessel disease after inferior myocardial infarction

We correlated clinical parameters with angiographic findings in 108 men with a previous isolated inferior myocardial infarction, to determine if these parameters could predict accurately which patients had multivessel disease. Of 71 men in angina class 2-3, 42 had three vessel disease versus only seven of the 37 who were either asymptomatic or angina class 1 (P less than 0.001). Multivessel disease was present in 35 of the 36 who had anterior ST-T abnormalities at rest (P less than 0.001) and 16 of the 17 with cardiomegaly. Among men 55 years and older, the incidence of multivessel disease was 94% compared to 70% in men less than 55 (P less than 0.03). We conclude that functional angina class, age, and the presence of resting anterior ST and T abnormalities are highly predictive of associated left system disease in survivors of inferior infarction.

Fascicular conduction distrubances after coronary bypass surgery

Two hundred patients underogoing coronary bypass graft surgery were studied to determine the frequency and significance fo new fascicular conduction distrubances. The follow-up period ranged from 13 to 39 months. New disturbances developed in 39 patients (20 percent). Isolated right bundle branch block (6 percent) and left anterior hemiblock (6 percent) were the most common disturbances. Righ bundle branch block was usually transient and was not associated with further complications in the follow-up period. However, patients with either transient or persistent left bundle branch block or left anterior hemiblock, or both, had (1) increased later mortality compared with patients without new fascicular conduction disturbances (5 of 26 versus 11 of 161; P less than 0.02), and (2) increased late myocardial infarction (2 of 26 versus 2 of 161; P less than 0.05). New left fascicular conduction disturbances after coronary surgery identified a subset of patients with more extensive ischemic heart disease, suggesting that these patients require close follow-up care.