Fifteen-year results of coronary artery bypass for isolated left anterior descending coronary artery disease

Modeling the costs and outcomes of cardiovascular surgery

Coronary artery bypass graft (CABG) operations consume more health care resources than any other single procedure. The objective of this study was to develop a computer simulation model that can be used to predict costs and patient outcomes of CABG surgery. The analysis is based on a systems dynamic model developed using STELLA software. Two sets of data from Medicare patients who underwent CABG operations at Methodist Hospital of Indiana were used to construct and validate the model. The model predictions of length of hospital stay, use of specialists in caring for patients, costs and postoperative functional status are reasonably close to actual data on patients who underwent CABG surgery. The analysis indicates the most important factors affecting costs and outcomes are gender, age, whether or not the surgery is a reoperation and whether the patient experiences postoperative complications. The model can be used to predict costs and outcomes for a patient population from a small set of preoperative characteristics (i.e., age, gender, DRG, whether the surgery is a reoperation, and the patient's operative status). A second potential use of the model is to answer clinical questions such as do the costs and risks of CABG operations outweigh the benefits for patients with certain risk factors.

Minimally invasive single-vessel coronary artery bypass with the internal thoracic artery and early postoperative angiography: midterm results of a prospective study in 120 consecutive patients

BACKGROUND

This prospective study was undertaken to determine the role of the minimally invasive direct coronary artery bypass with early postoperative angiography and midterm follow-up in 120 consecutive patients with single-vessel coronary artery disease.

METHODS

Minimal access (6 to 10 cm), without complete sternotomy and no cardiopulmonary bypass, was used. The lesions were located at the proximal left anterior descending coronary artery in 95% of the patients. Routine coronary angiography was performed before discharge.

RESULTS

Postoperative angiography was performed in 104 (90.4%) of those 115 patients who had coronary revascularization concluded by the mini-access method. The internal thoracic artery patency rate was 98.1% (95.2% grade A). Two (1.7%) patients presented with perioperative myocardial infarction, which led to the single in-hospital death (0.8%). Of the remaining 119 patients, 113 (95.0%) were asymptomatic. The event-free probability was 94.9% and the actuarial survival was 98.3% with 42 months of follow-up.

CONCLUSIONS

For selected patients with single-vessel coronary artery disease and no major myocardial dysfunction, minimally invasive direct coronary artery bypass is a safe operation and a less invasive alternative to conventional coronary artery bypass grafting.

[Arterial myocardial revascularization in the 9th decade of life. Personal results and review of the literature]

The rate of the population being 80 years of age and even older, has an increasing tendency in the Federal Republic of Germany. In 1996, a total of 87,372 patients received surgery supported by the heart-lung-machine, 2,383 patients out of these (2.7%) were 80 years of age and older. In view of the limited life expectance, the arterial revascularization in this age category is faced with controverse discussions. We analysed our patients in relation to this aspect. Between January 1, 1995 and June 30, 1997, 4,338 patients underwent surgery supported by the heart-lung-machine. Hundred and fifty-five out of these (3.6%) were in the 9th decade of life. Seventy-seven patients out of the 155 (49.7%, 34 women, 43 men, 80 to 88 years old, mean: 82 years of age) underwent an isolated myocardial revascularization. We performed 55 (71%) elective, 16 (21%) urgent and 6 (8%) emergency surgeries. Twelve patients (15.6%) solely received venous bypasses (Group I), 65 (84.4%) additionally also received unilateral bypasses of the internal mammaria artery (IMA) (Group II). Three patients died at our facility (3.9%), 3 further patients died during the follow-up treatment in outlying hospitals, the in-patient mortality rate in Group I therefore presented a rate of 8.3%, in Group II 7.7% and in total, a rate of 7.8%. In 1996, the in-patient mortality rate could be reduced to 3.6%. The follow-up observation time ranged between 7 and 138 weeks (median 44 weeks). The survival rate for patients with an IMA-bypass after 1 year was 86.3%, after 2 years 77%, and for the entire collective 85.3% and 75%. Whereas 96% of the patients could pre-operatively be related to Class III or IV of the NYHA-classification, 55 of the 63 survivors (87%) belonged to Class I (6%) or II (81%). Two Group I patients (22.2%), 3 Group II patients (5.6%) and 7.9% of the total collective complained about repeated angina symptoms. The myocardial revascularization with the internal mammaria artery performed on patients in the 9th decade of life, achieves an acceptable morbidity and mortality compared to solely venous coronary bypasses. The more prolonged follow-up observation period will clarify, whether the arterial myocardial revascularization also proves to be the superior method in this age category.

Does it make sense to use two internal thoracic arteries?

Retrospectively, the first 143 patients who were operated on with bilateral internal thoracic arteries (BITA group) were matched with 143 patients operated on with only one left internal thoracic artery anastomosed on the left anterior descending artery and additional vein grafts (LITA group) and followed up for a maximum of 8 years. At 5 years follow-up there were no significant differences in event-free survival between the groups. After 8 years, the overall survival was 96% and 92% (not significant [NS]), cardiac survival 99% and 97% (NS), angina-free cardiac survival 51% and 35% (NS), infarction-free cardiac survival 95% and 78% (NS), reintervention-free cardiac survival 87% and 88% (NS), and all cardiac event-free survival 49% and 31% (NS) for the BITA and LITA groups, respectively. The incidence of late pulmonary, wound, and other complications was comparable. Cox proportional hazards analysis showed that a higher left ventricular end-diastolic pressure and female sex were predictors of recurrent angina and late cardiac events. During this intermediate-term follow-up, the use of one or two internal thoracic arteries was of no value in predicting angina-free or cardiac event-free survival.

Evaluating the potential cost-effectiveness of stenting as a treatment for symptomatic single-vessel coronary disease. Use of a decision-analytic model

BACKGROUND

Coronary stenting appears to provide more predictable immediate results and lower rates of restenosis than conventional balloon angioplasty for selected lesion types, but its hospital costs are significantly higher. This study was designed to evaluate the potential cost-effectiveness of Palmaz-Schatz coronary stenting relative to conventional balloon angioplasty for the treatment of patients with symptomatic, single-vessel coronary disease.

METHODS AND RESULTS

We developed a decision-analytic model to predict quality-adjusted life expectancy and lifetime treatment costs for patients with symptomatic, single-vessel coronary disease treated by either Palmaz-Schatz stenting (PSS) or conventional angioplasty (PTCA). Estimates of the probabilities of overall procedural success (PTCA, 97%; PSS, 98%), abrupt closure requiring emergency bypass surgery (PTCA, 1.0%; PSS, 0.6%), and angiographic restenosis (PTCA, 37%; PSS, 20%) were derived from review of the literature published as of September 1993. Procedural costs were based on the true economic (ie, variable) costs of each procedure at Boston's Beth Israel Hospital. On the basis of these data, coronary stenting was estimated to result in a higher quality-adjusted life expectancy than conventional angioplasty but to incur additional costs as well. Compared with conventional angioplasty, stenting had an estimated incremental cost-effectiveness ratio of $23,600 per quality-adjusted life year gained. Although the cost-effectiveness ratio for stenting changed with variations in assumptions about the relative costs and restenosis rates, it remained less than $40,000 per quality-adjusted year of life gained--and thus was similar to many other accepted medical treatments--unless the stent angiographic restenosis rate was > 23%, the angioplasty restenosis rate was < 34%, or the cost of stenting (including vascular complications) exceeded that of conventional angioplasty by more than $3000. The alternative strategy of secondary stenting (initial angioplasty followed by stenting only for symptomatic restenosis) was estimated to be both less effective and less cost-effective than primary stenting over a wide range of plausible assumptions and thus does not appear to be cost-effective when primary stenting is also an option.

CONCLUSIONS

Decision-analytic modeling can be used to evaluate the potential cost-effectiveness of new coronary interventions. Our analysis suggests that despite its higher cost, elective coronary stenting may be a reasonably cost-effective treatment for selected patients with single-vessel coronary disease. Primary stenting is unlikely to be cost-effective for lesions with a low probability of restenosis (eg, < 30%) or for patients for whom the cost of stenting is expected to be much higher than usual (eg, because of a high risk of vascular complications). Given the sensitivity of the cost-effectiveness ratios to even modest variations in the relative restenosis rates and cost estimates, future studies will be necessary to determine more precisely the cost-effectiveness of coronary stenting for specific patient and lesion subsets.

Prediction of sudden cardiac arrest: risk stratification by anatomic substrate

The prognostic importance of coronary artery anatomy to specific outcomes including ventricular tachycardia/fibrillation was evaluated in 372 consecutive patients undergoing cardiac catheterization at University Hospital at Stony Brook between 1981 and 1984. The hypothesis that proximal left anterior descending artery narrowing before the first septal perforator had a specific relationship to survival was again tested in this cohort. The population was prospectively followed for 8 years, with all clinical management decisions made independently by the patient's primary or referring physician. Multivariate statistical and life table analyses were performed after comprehensive follow-up. Significant narrowing in the proximal left anterior descending artery was associated with an increased risk of sudden cardiac death (p = 0.0002). Abnormalities of contractility in the diaphragmatic segment of the left ventricle in addition to an elevation of the left ventricular end-diastolic pressure and the presence of congestive heart failure (p < 0.05) were other contributory variables. Outcome in patients with proximal left anterior descending coronary artery disease who underwent aortocoronary artery bypass to the artery demonstrated improved survival (p < 0.05). Risk stratification of patients at high risk for sudden cardiac death is possible and may allow identification for an aggressive approach or interventional trials.