Improved longevity due to reduction of sudden death by aortocoronary bypass in coronary atherosclerosis

Amplification of coronary arteriogenic capacity of multipotent stromal cells by epidermal growth factor

OBJECTIVE

We determined whether increasing adherence of multipotent stromal cells (MSCs) would amplify their effects on coronary collateral growth (CCG).

METHODS AND RESULTS

Adhesion was established in cultured coronary endothelials cells (CECs) or MSCs treated with epidermal growth factor (EGF). EGF increased MSCs adhesion to CECs, and increased intercellular adhesion molecule (ICAM-1) or vascular cell adhesion molecule (VCAM-1) expression. Increased adherence was blocked by EGF receptor antagonism or antibodies to the adhesion molecules. To determine whether adherent MSCs, treated with EGF, would augment CCG, repetitive episodes of myocardial ischemia (RI) were introduced and CCG was measured from the ratio of collateral-dependent (CZ) and normal zone (NZ) flows. CZ/NZ was increased by MSCs without treatment versus RI-control and was further increased by EGF-treated MSCs. EGF-treated MSCs significantly improved myocardial function versus RI or RI+MSCs demonstrating that the increase in collateral flow was functionally significant. Engraftment of MSCs into myocardium was also increased by EGF treatment.

CONCLUSIONS

These results reveal the importance of EGF in MSCs adhesion to endothelium and suggest that MSCs may be effective therapies for the stimulation of coronary collateral growth when interventions are used to increase their adhesion and homing (in vitro EGF treatment) to the jeopardized myocardium.

The effect of coronary artery bypass grafting on specific causes of long-term mortality in the Bypass Angioplasty Revascularization Investigation

OBJECTIVES

We sought to examine the effect of revascularization with coronary artery bypass grafting on specific causes of death in the Bypass Angioplasty Revascularization Investigation cohort. Although the effect of coronary revascularization on long-term mortality has been previously described, there are limited data describing its effect on specific causes of death in patients with coronary artery disease. Evaluation of cause of death might help elucidate disease mechanisms and be useful for developing treatment strategies.

METHODS

In the Bypass Angioplasty Revascularization Investigation randomized trial and registry, 3610 patients underwent initial revascularization with coronary artery bypass grafting or balloon angioplasty and were followed for an average of 7.7 years. Causes of all deaths were classified by an independent committee.

RESULTS

Among 3610 revascularized patients, 2239 underwent coronary artery bypass grafting as an initial or subsequent procedure. Over 7.7 years of follow-up, 3% of all patients died of sudden cardiac death, 3% died of myocardial infarction-related death, 2% died of congestive heart failure and other cardiac causes, and 9% died of noncardiac causes. Coronary artery bypass grafting (vs no coronary artery bypass grafting) was associated with a significantly lower risk of sudden cardiac death (relative risk, 0.60; P = .01) but was not significantly associated with any other causes of long-term mortality.

CONCLUSIONS

In the Bypass Angioplasty Revascularization Investigation coronary artery bypass grafting significantly decreased the risk of sudden cardiac death but not any other cause of long-term mortality. Because major risk factors for sudden cardiac death have historically favored a revascularization strategy of coronary artery bypass grafting over angioplasty, evaluation of the current practice of extending angioplasty as an alternative to coronary artery bypass grafting in similar high-risk subgroups is paramount.

Surgical management of ventricular tachycardia

BACKGROUND

Ventricular tachyarrhythmias are the leading cause of death from coronary artery disease. A small percentage of these arrhythmias originate in chronically ischemic myocardium, rather than acutely ischemic myocardium, and can be refractory to medical management. Epicardial mapping and focal cryoablation of foci demonstrating early activation may provide definitive therapy when pharmacologic management fails. We report a series of 42 consecutive patients with refractory ventricular tachycardia (VT) who were treated with open epicardial mapping and focal cryoablation after pharmacologic management failed.

METHODS

We retrospectively reviewed the records of patients who underwent surgical treatment of malignant VT. For patients not recently seen in the clinic, we conducted telephone interviews. At the time of operation, epicardial mapping was performed to locate foci of early electrical activation. These foci were then cryoablated, using 2-minute applications of liquid nitrogen-cooled probes. All patients underwent postoperative electrophysiologic studies to test for inducible VT.

RESULTS

Of these 42 patients, 34 (81%) were male, 8 (19%) female. Average age was 62.9 +/- 10.6 years; ejection fraction, 0.20 (range, 0.04 to 0.50); and number of foci ablated, 2.1 +/- 1.1 (range, 1 to 6). At the time of cryoablation, all patients underwent additional procedures, including aneurysmectomy, coronary artery bypass, or valve replacement. The 30-day operative mortality was 9.5% (4 of 42). Of the 38 survivors, 36 (94.7%) were clinically free of VT; the remaining 2 had spontaneous or inducible VT.

CONCLUSIONS

Open cryoablation of foci propagating VT appears to be safe and effective. It may be the most definitive treatment for malignant VT.

Effect of antithrombotic therapy on risk of sudden coronary death in patients with congestive heart failure

Data from epidemiologic, autopsy, Holter monitoring, and electrophysiologic studies support the hypothesis that acute myocardial ischemia, even in the absence of myocardial infarction, is a critical component of the pathophysiology of sudden coronary death. Acute myocardial ischemia superimposed upon ventricles damaged from previous infarctions has been demonstrated to enhance the generation of lethal ventricular arrhythmias. This is a retrospective analysis of 6,797 participants in the Studies of Left Ventricular Dysfunction prevention and treatment trials. Both univariate and multivariate Cox proportional-hazards modeling were used to study the association of anticoagulant and antiplatelet therapy with the risk for sudden cardiac death. The following covariates were adjusted for in the analysis: age, ejection fraction, gender, atrial fibrillation, diabetes, a history of angina, prior infarction, prior revascularization, and the regular use of beta blockers, diuretics, digoxin, antiarrhythmic agents, or enalapril. The overall incidence of sudden cardiac death per 100 patient-years of follow-up was 2.24%. In multivariate analysis, antiplatelet and anticoagulant monotherapy each remained independently associated with a reduction in the risk of sudden cardiac death: antiplatelet therapy with a 24% reduction (relative risk [RR] 0.76; 95% confidence interval [CI] 0.61-0.95) and antiplatelet monotherapy with a 32% reduction (RR 0.68; 95% CI 0.48-0.96). Thus, in patients with moderate to severe left ventricular systolic dysfunction resulting from coronary artery disease, antiplatelet and anticoagulant therapy are each associated with a reduction in the risk of sudden cardiac death.

Operation for ventricular tachyarrhythmias: refining current treatment strategies

For many patients with ventricular tachyarrhythmias, the optimal choice of palliative or curative therapies is not yet well established. To refine optimal current treatment strategies, baseline patient characteristics were studied in relation to likelihood of successful outcome in 240 consecutive patients undergoing operation for treatment of ventricular tachyarrhythmias from 1981 to 1991. Indications for operation were sudden cardiac death or inducible ventricular tachyarrhythmias refractory to medical therapy (or both). Treatment was directed endocardial procedures in 77 patients (32%), other cardiac procedures in 57 patients (24%) (coronary artery bypass grafting in 94% and valve procedure in 14%, either with [35%] or without [65%] concomitant implantable cardioverter-defibrillator), and implantable cardioverter-defibrillator alone in 106 patients (44%). Overall 30-day operative mortality was 5% (70% confidence interval, 4%-7%) and 2-year survival was 74% (70% confidence interval, 71%-77%). Overall 2-year freedom from sudden cardiac death was 97% (70% confidence interval, 96%-98%) and was similar (p = not significant) for all treatment modalities. For each treatment modality, multivariate analysis identified independent risk factors for operative mortality and 2-year tachyarrhythmia recurrence, advanced angina and congestive heart failure New York Heart Association classes, and overall mortality. To characterize better the use and benefit of coronary artery bypass grafting, risk factors related to outcome also were identified for patients stratified according to absence (44 patients) or presence (119 patients) of coronary artery disease excluding patients treated by directed endocardial procedures.(ABSTRACT TRUNCATED AT 250 WORDS)

Risk and benefit of additional aortocoronary bypass grafting in patients undergoing cardioverter-defibrillator implantation

It is unclear whether additional aortocoronary bypass grafting should be performed in patients who need an automatic implantable cardioverter defibrillator (ICD) in one- or two-step procedures. Therefore we studied the follow-up of 139 patients who underwent epicardial implantation of the cardioverter defibrillator (CD). All patients had coronary artery disease and recurrent ventricular tachycardia or fibrillation. Eighty-nine patients had implantation of the CD without additional surgical approaches (group G1), and 50 patients had concomitant aortocoronary bypass grafting (group G2). Perioperative mortality (within 30 days after CD implant) was 1 (1%) of 89 patients in G1 and 6 (12%) of 50 patients in G2 (p < 0.01). During the mean follow-up of 26 +/- 20 months, sudden death occurred in four (4%) of 89 patients in G1 and two (4%) of 50 patients in G2. Twenty-three (17%) patients died of cardiac failure (18 [20%] patients in G1 and 5 [10%] patients in G2). ICD discharges occurred in 69 (78%) of 89 patients in G1 and in 36 (72%) of 50 patients in G2. The mean incidence of ICD discharges was 23 +/- 69 shocks per patient in G1 and 18 +/- 25 shocks per patient in G2 (p = NS). We conclude that concomitant aortocoronary bypass grafting during CD implantation leads to a higher perioperative mortality. Avoidance of myocardial ischemia does not significantly influence sudden death mortality nor markedly reduce the number of ICD discharges.

Influence of coronary bypass surgery on subsequent outcome of patients resuscitated from out of hospital cardiac arrest

The effect of coronary bypass surgery on recurrent cardiac arrest was estimated in 265 patients resuscitated from out of hospital cardiac arrest between 1970 and 1988. From this cohort, 85 patients (32%) underwent coronary bypass surgery after recovery from cardiac arrest and 180 patients (68%) were treated medically. A multivariate Cox analysis was used to estimate the effect of coronary bypass surgery on subsequent survival after adjusting for effects of age, prior cardiac history, ejection fraction, year of the event, history of angina, antiarrhythmic drug use and whether the arrest was related to acute myocardial infarction. The use of coronary bypass surgery had a significant effect in reducing the incidence of subsequent cardiac arrest during follow-up study (risk ratio [RR] 0.48, 95% confidence interval [CI] 0.24 to 0.97, p less than 0.04). There was also a trend consistent with a reduction in total cardiac mortality (RR 0.65, 95% CI 0.39 to 1.10, p = 0.10). These findings suggest that coronary bypass surgery may reduce the incidence of sudden death in suitable patients resuscitated from an episode of ventricular fibrillation.

Surgical therapy for drug-refractory ventricular tachycardia: role of additional aneurysmectomy or bypass grafting

To assess whether additional aneurysmectomy and/or bypass grafting influence prognosis we studied 97 patients with recurrent sustained monomorphic ventricular tachycardia after an old myocardial infarction. All patients underwent subendocardial resection due to drug-refractory ventricular tachycardia. There were 41 patients who had resection alone, 27 patients had resection and aneurysmectomy, 13 patients had resection and bypass grafting and the remaining 16 patients had resection with both, aneurysmectomy and bypass grafting. During the mean follow-up of 40 +/- 27 months 29 patients died (30%) (total mortality), 7 patients suddenly (7%) and 20 patients from cardiac causes (20%). There were no significant differences in total mortality between patients with resection alone (32%), patients with resection and aneurysmectomy (22%), patients with resection and bypass grafting (31%) and patients who had resection, aneurysmectomy and bypass grafting (38%). In addition, no significant differences were observed in the incidence of sudden death and nonfatal recurrences between patients with resection alone: sudden death 12%, recurrences 7%; patients with resection and aneurysmectomy: sudden death 0%, recurrences 19%; patients with resection and bypass grafting: sudden death 0%, recurrences 8%; and patients with resection, aneurysmectomy and bypass grafting: sudden death 13%, recurrences 0%. Postoperatively, left ventricular function improved in 56% of patients who had resection and aneurysmectomy compared to 17% of patients with resection alone, 31% of patients with resection and bypass grafting and 19% of patients who had resection, aneurysmectomy and bypass grafting. There is a low risk of sudden death and nonfatal recurrences after subendocardial resection. An influence of additional surgical approaches (aneurysmectomy or bypass grafting) on prognosis is not visible.

Medical and surgical management of early Q wave myocardial infarction. I. Effects of surgical reperfusion on survival, recurrent myocardial infarction, sudden death and functional class at 10 or more years of follow-up

To define the outcome of patients given medical or surgical therapy for Q wave myocardial infarction, 387 patients were followed up for 10 to 13 years (mean 11.4). On study entry the groups had similar distributions for variables such as mean age, gender, previous myocardial infarction, abnormal creatine kinase activity, area of infarction, number of vessels diseased and clinical classification. The hospital mortality rate of the medical versus surgical group was 11.5% (23 of 200) versus 5.8% (11 of 187) (p = 0.07). Early reperfusion (that is, less than or equal to 6 h) resulted in a lower mortality rate than did medical therapy--2% (2 of 100) versus 11.5% (23 of 200) (p less than 0.05)--whereas the hospital mortality rate with late reperfusion was 10.3% (9 of 87). The long-term mortality rate of the medical and surgical groups was 41% (82 of 200) versus 27% (51 of 187) (p = 0.0007) with use of an adjusted Cox proportional hazards model. In the survivors, the differences between medical and surgical groups in recurrent myocardial infarction, mortality associated with reinfarction and sudden death were prospectively followed and evaluated by the life table method. Recurrent myocardial infarction was not prevented by surgical reperfusion or medical therapy (23% in both groups), however, the mortality rate in patients with recurrent infarction was higher in the medical therapy group--36.6% (15 of 41) versus 17.5% (7 of 40) (p = 0.04). The mortality difference did not depend on early or late surgical reperfusion. In the in-hospital survivors, the incidence of sudden death was 17.5% in the medical (31 of 177) versus 7.4% (13 of 176) in the surgical group (p = 0.01). This difference was much more pronounced in the early reperfusion group. Functional class was significantly lower than that for medical therapy in the early reperfusion but not the late reperfusion group. Thus, in comparable groups given medical and surgical therapy for acute myocardial infarction and followed up for greater than or equal to 10 years, surgical reperfusion appears to offer improved longevity in selected cases (when implemented early) but does not prevent recurrent myocardial infarction. The associated mortality with recurrent myocardial infarction is less as is the incidence of sudden death. Finally, lower functional class occurs most often in patients given early reperfusion.

Sudden cardiac death: etiologies, pathogenesis, and management

Sudden death claims an estimated 350,000 lives per year in the United States. When death occurs within 1 hour of the onset of symptoms, 90% are the result of ventricular tachyarrhythmias. The majority of victims are middle-aged men with coronary artery disease, but in approximately 25%, sudden death is the presenting manifestation of their problem. In some populations, the detection of premature ventricular complexes (PVCs) by ambulatory monitoring is predictive of an increased risk of sudden death. However, the arrhythmia that best predicts this risk is unclear, and ambient arrhythmias are only a modest marker of this risk. Therapy to suppress asymptomatic PVCs has not been shown to be effective in preventing sudden death, and in some cases, lethal arrhythmias can be prevented without significant effects on ambient arrhythmias. Other risk markers such as depressed left ventricular function and the presence of low-amplitude, long-duration, late potentials recorded on a signal averaged electrocardiogram are more powerful predictors of risk than are PVCs. These latter findings in particular support the presence of areas of slow electrical conduction (a requirement for reentrant mechanism arrhythmias) and suggest that an abnormal electrical environment or "substrate" is the most important factor in this problem. The management of patients at risk for sudden death is controversial. While postinfarct survivors with arrhythmias constitute a population at increased risk, the absolute risk is only about 5% in the first year and has not been shown to be improved by conventional antiarrhythmic drugs. Small study size, arrhythmia variability, ill-defined end points, and proarrhythmia may partially explain this apparent lack of efficacy. The prophylactic use of antiarrhythmic drugs other than beta-blockers to prevent sudden death in asymptomatic populations at risk is therefore of unproven benefit. By contrast, patients who have survived a life-threatening arrhythmia unrelated to an acute myocardial infarction have an approximately 30% risk of recurrence in the following year. In these patients, the use of ambulatory monitoring to guide therapy is limited by the high incidence of false-negative responses (lethal arrhythmia recurrence despite ambient arrhythmia suppression) and the lack of frequent spontaneous arrhythmias in many patients. In this patient population, electrophysiological testing can be used to prognosticate recurrence and gain insight into arrhythmia mechanism, stability, and hemodynamic tolerance. The technique is also useful in guiding both pharmacological and nonpharmacological therapy.(ABSTRACT TRUNCATED AT 400 WORDS)

Risk factor profiles of patients with sudden cardiac death and death from other cardiac causes: a report from the Coronary Artery Surgery Study (CASS)

Identification of patients at risk of sudden death is essential if optimal preventive treatment strategies are to be developed. In the Coronary Artery Surgery Study (CASS) Registry, 19,946 patients were analyzed to characterize baseline clinical, hemodynamic and angiographic features of patients dying from sudden cardiac death and to compare them with features of patients dying from other cardiac causes, of those dying from noncardiac causes and of survivors. Of the 11,843 medically treated patients, 1,621 died during a mean follow-up period of 5.0 years: death was sudden in 557 (34%), nonsudden but cardiac in 813 (50%) and noncardiac in 251 (16%). In 8,103 surgically treated patients, 824 deaths occurred during a mean follow-up period of 5.1 years: death was sudden in 204 (25%), nonsudden but cardiac in 390 (47%) and noncardiac in 230 (28%). In general, the patients (both medically and surgically treated) who died of cardiac causes, either suddenly or nonsuddenly, were similar to each other but significantly different from patients who either survived or died of noncardiac causes. Although patients with an increased risk of any type of cardiac death could be identified, there were no measures of angiographic or hemodynamic characteristics that were significantly different between patients with sudden cardiac death and those with nonsudden cardiac death. Identification of patients at high risk for sudden cardiac death will require approaches in addition to clinical, angiographic and hemodynamic assessment, such as electrophysiologic assessment or monitoring techniques to identify triggering mechanisms.

CASS in retrospect: lessons from the randomized cohort and registry. Coronary Artery Surgery Study

The Coronary Artery Surgery Study (CASS) was a prospective, randomized evaluation of the value of coronary artery bypass grafting compared with medical therapy for stable, mildly symptomatic coronary artery disease. Also, the CASS registry collected clinic information and follow-up data from 24,959 nonconsecutive patients undergoing cardiac catheterization from 1974 to 1979. CASS has had a major impact on current management of the coronary disease patient and represents an important contribution to the cardiovascular knowledge base. Despite the large size and valuable contributions of CASS, its findings have been widely misinterpreted, especially regarding indications for coronary artery bypass surgery. This review examines CASS from the viewpoint of its methodology and some of its many published reports. A full understanding of CASS is requisite to avoid clinical misapplication of the findings of this study.

The effect of medical and surgical treatment on subsequent sudden cardiac death in patients with coronary artery disease: a report from the Coronary Artery Surgery Study

The effect of medical and surgical treatment on subsequent sudden cardiac death was assessed in 13,476 patients in the Coronary Artery Surgery Study registry who had significant coronary artery disease, operable vessels, and no significant valvular disease. (Patients were assigned to medical or surgical therapy on the basis of clinical judgment and not according to a randomization scheme; therefore, biases associated with unknown variables could not be evaluated.) Sudden cardiac death occurred in 452 patients (3.4%) during a mean follow-up of 4.6 years. Five year survival free of sudden death for medically treated patients was 94 +/- 0.3%, and that for surgically treated patients was 98 +/- 0.2% (p less than .0001). Twelve baseline clinical, electrocardiographic, and angiographic variables were significantly different between patients alive at the last follow-up and those suffering sudden death. Data on these variables were available for 11,508 patients. Sudden death occurred in 257 (4.9%) of 5258 medically treated and 101 (1.6%) of 6250 surgically treated patients. In a high-risk patient subset with three-vessel disease and history of congestive heart failure, 91% of surgically treated patients had not suffered sudden death compared with 69% of medically treated patients. After Cox survival analysis was used to correct for baseline variables, surgical treatment had an independent effect on sudden death (p less than .0001). This reduction was most pronounced in high-risk patients.

Long-term follow-up of survivors of prehospital sudden cardiac death treated with coronary bypass surgery

Although coronary artery bypass surgery is beneficial to patients with severe coronary artery disease, its role in preventing the recurrence of prehospital cardiac arrest in patients is not clear. In this article, we report on the long-term follow-up of 49 survivors of prehospital coronary arrest who had coronary artery bypass surgery. Prior to their prehospital cardiac arrest, 14% of the patients had a history of unstable angina. Coronary angiograms obtained after prehospital cardiac arrest showed that 71% of the patients had three-vessel coronary artery disease and 6% had single-vessel disease. The mean left ventricular ejection fraction was 45%. There were four postoperative deaths; three were caused by pump failure, and one was caused by refractory ventricular arrhythmias. After a maximum follow-up period of 102 months (mean of 55.4 months), there were seven cardiac deaths; five of the patients died of recurrent ventricular fibrillation, and two patients' deaths were related to refractory heart failure. Actuarial analyses of the 49 patients showed that the probability of survival at 6 months, 1 year, 2 years, 3 years, and 5 years was 92%, 92%, 89%, 82%, and 72%, respectively. After surgery, 35 of the 45 patients who were discharged from the hospital were asymptomatic, and 23 of the 32 patients who were employed when their prehospital cardiac arrest occurred returned to their employment. We concluded that coronary artery bypass surgery is beneficial to certain survivors of prehospital sudden death. After surgery, most patients are asymptomatic and capable of returning to their employment and the recurrence of prehospital sudden death is low.

Myocardial perfusion after aortocoronary bypass surgery: measurements at rest and after administration of isoproterenol

This study examined quantitative regional myocardial perfusion (RMP) measured by the washout of 133Xe at rest and after an isoproterenol challenge in 50 patients (group I) studied 8 to 14 days after they underwent saphenous vein bypass grafting to the left coronary artery, and compared this with RMP measured in the native left coronary artery in 14 patients (group II) with significant coronary artery disease and in 12 normal subjects (group III). The double product of the heart rate and aortic systolic pressure was used as an indicator of demand. The statistical significance of group comparisons was analyzed with Dunn's multiple comparisons among means test. Analysis of the data showed no significant difference among the groups with respect to aortic systolic pressure. In subjects at rest, heart rate was lower in groups II and III than in group I, and double product was lower in group II than in group I. After isoproterenol, both heart rate and double product were lower in group II compared with groups I and III, but there was no significant difference between groups I and III with respect to heart rate or double product. Mean resting RMP in group II was lower than in group I; however, results of other group comparisons were insignificant for resting parameters. After isoproterenol, mean flow (ml/100 g/min) in group I was similar to flow in group III (130 +/- 24 vs 139 +/- 26). In contrast, the average flow response after isoproterenol was significantly less in group II when compared with that in group I (105 +/- 20 vs 130 +/- 24) and with that in group III (105 +/- 20 vs 139 +/- 26). Because of differences in levels of demand with isoproterenol, the change in flow was normalized to the percent increase in double product. These data showed results similar to those above, i.e., normalized RMP in patients with coronary artery disease was significantly lower than that in normal subjects (82 +/- 41 vs 119 +/- 57) and in revascularized patients (82 +/- 41 vs 105 +/- 54). However, there was no significant difference between normal subjects and patients who had undergone surgery. To further evaluate the relationship of flow response to demand parameters, we plotted RMP/double product vs resistance. The data revealed a significant correlation between these variables in all groups both in subjects at rest and after isoproterenol.(ABSTRACT TRUNCATED AT 400 WORDS)

Prevalence and clinical significance of the repetitive ventricular response during sinus rhythm in coronary disease patients

The prevalence of the repetitive ventricular response (RVR) after single and double premature stimulation during sinus rhythm or a paced supraventricular rhythm at a rate of 85 bpm was assessed in 343 patients (group 1: 237 patients studied prospectively who were referred for coronary arteriography and ventriculography; group 2: 44 patients after recent acute myocardial infarction; group 3: 61 patients with documented ventricular tachycardia and/or fibrillation). In group 1 patients, RVR testing was performed from both the right ventricular apex (n = 237) and outflow tract (n = 190), whereas in the remaining patients only the apex was stimulated. In group 1, RVR after a single premature stimulus occurred in 21.9% and after two stimuli in 63.2%. In patients with normal left ventricular (LV) function (n = 63) the prevalence of RVR after a single stimulus was significantly less (9.5%) than in those with LV dysfunction (n = 174;26.4%,p less than 0.01). However, after double stimulation, there was no longer any difference. In group 2, the prevalence of RVR was 25% after one and 34.1% after two premature stimuli. In group 3 patients, RVR was observed in only 14.8% after one and in 41% of patients after two premature stimuli. Ventricular tachycardia (greater than or equal to 10 QRS) was induced in nine patients during a supraventricular rhythm. Two hundred thirty-seven patients of group 1, who were prospectively studied in order to assess the prognostic significance of the RVR, were followed for a mean period of 27.2 +/- 10.7 months.(ABSTRACT TRUNCATED AT 250 WORDS)

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.

Effect of coronary vasodilation on ventricular fibrillation threshold: role of exogenous vasodilators and perfusion conditions

Even without myocardial ischemia, coronary blood flow (CBF) constitutes a major determinant of ventricular fibrillation threshold (VFT). To clarify whether abnormal distribution of normal or increased CBF plays any additional role, 14 open-chest chloralose-anesthetized dogs with fixed-normalized heart rate, cardiac output, and systemic arterial pressure and separate servocontrolled left main coronary artery perfusion were studied as follows: VFT was determined first with coronary perfusion pressure (CPP) set at systemic level (80 mm Hg). Then CBF index was fixed at control levels (134.0 +/- 9.5 ml/min X 100 gm-1 LV) and coronary vasodilation was induced by intracoronary infusion of adenosine until CPP decreased to 49.0 +/- 2.0 mm Hg. Myocardial O2 consumption, LV pressure, LV dp/dt, and surface ECG remained unchanged. However, VFT decreased in all trials by about 45% (p less than 0.001). When CPP was reset to 80 mm Hg while maintaining vasodilation, CBF index increased by 90% to 255.4 +/- 15.4 ml/min X 100 gm-1 LV and VFT by 26% (p less than 0.005) from control. Yet these VFT increases in response to intraluminal pharmacologic vasodilation were about 19% (p less than 0.002) lower than expected for similar CBF index increases occurring physiologically. We conclude that intraluminal coronary vasodilation not matched by appropriate CBF increase results in substantial decrease of VFT. Moreover, at comparable increase of CBF, spontaneous physiologic vasodilation is more effective than intraluminal pharmacologic coronary vasodilation in increasing VFT.

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 prognosis in survivors of myocardial infarction: a prospective clinical angiographic study

To identify predictors of late mortality, 259 consecutive men (less than or equal to 60 years old) who survived acute myocardial infarctions were catheterized one month after admission and were then followed for a mean of 34 months. Nineteen patients (7 per cent) died during the observation period. Of 79 base-line descriptors, 17 proved to be univariate predictors of survival. Cox regression analysis demonstrated that the ejection fraction (P less than 0.001), the number of diseased vessels (P less than 0.005), and the occurrence of congestive heart failure in the coronary unit (P less than 0.01) were the only independent predictors of survival. Risk stratification showed that the probability of survival at four years was highest in patients with normal ejection fractions (96 to 100 per cent, depending on the number of diseased vessels) and lowest in those with ejection fractions below 20 per cent (3o to 75 per cent). The prognosis in patients with ejection fractions between 21 and 49 per cent was significantly worse (78 per cent) than in those with normal ejection fractions only in the group with three-vessel involvement (P less than 0.01). Since most survivors of myocardial infarction who are likely to have their lives prolonged by coronary-artery bypass surgery are in this group, it is reasonable to limit routine coronary angiography to the 56 per cent of survivors who have ejection fractions between 21 and 49 per cent.

Coronary artery graft surgery

The last decade has seen significant technical advances in equipment for the procedure of, and the surgeon's operating skill in coronary artery by pass surgery. Such surgery is indicated when, despite medical treatment, angina is disabling; although evidence is increasing that patients whose pain is controlled should be considered for surgery. Late operations are more complex and expensive, and patients are exposed to a higher risk of sudden death in the intervening period. Delay may also allow the disease to progress to an inoperable state. Patients unlikely to benefit from medical treatment should be offered surgery as soon as their disease is identified by angiography. Intensive medical treatment, with its poorer control of symptoms, leads to an increasing dependence on the State of medicine, hospital facilities and sickness benefits. The reputedly expensive coronary artery bypass operation is cheaper both to the State and to the patient tha unoperated invalidism.

Coronary revascularization surgery: feasibility after myocardial infarction

Since coronary revascularization improves prognosis in some patients with multivessel disease, can the potential benefits be extended to "prophylaxis" in selected postinfarction patients as well? These investigators sought the answer on the basis of patient characteristics, types of surgery, survival data, and mode of death in the postinfarction population of 129 patients who had early angiography.

Clinical, anatomic and functional descriptors influencing morbidity, survival and adequacy of revascularization following coronary bypass

Clinical data on 3,479 consecutive patients having coronary bypass surgery were retrospectively analyzed. Perioperative complications, incomplete revascularization, and reduced long-term survival could frequently be correlated with manifestations of myocardial damage. Patients with triple vessel and left main coronary disease had a greater frequency of inotropic requirements than did patients with single or double vessel disease (7.9% and 8.6% vs. 3.8% and 4.2%). Inotropic requirements in the perioperative period were significantly increased for patients with preoperative left ventricular dysfunction; a history of heart failure or multiple infarctions did not significantly increase the incidence of inotropic requirements. Presence of previous myocardial infarction, heart failure, or left ventricular contraction abnormalities significantly decreased the ability to achieve complete revascularization with bypass grafting. Hospital mortality since 1976 has been 0.8% (25/3,040). Hospital mortality was significantly increased by history of myocardial infarction, hypertension, heart failure, extent of anatomic disease, presence of preoperative ST-T wave changes, and severe abnormalities of left ventricular function. Hospital mortality in patients with ejection fraction </=0.35 was 3.4% vs. 1.3% for those >0.35. Anginal pattern, history of hypertension, previous myocardial infarction, preoperative heart failure all significantly affected long-term survival. Occurrence of perioperative myocardial infarction did not adversely influence long-term survival. Patients with normal left ventricular function had excellent 42 month survival regardless of vessel disease (95%, 96%, and 94% for single, double, and triple vessel disease, respectively). Survival was significantly less for such patients with abnormal left ventricular function. Inability to achieve complete revascularization did not adversely affect hospital mortality, but did significantly reduce late survival. The important effect which complete revascularization had on long-term survival appeared to increase with increasing severity of coronary disease. Although bypass grafting improves survival in patients with multivessel disease and left ventricular dysfunction, the benefits appear to be significantly reduced once manifestations of left ventricular damage have occurred.

Long-term results of myocardial revascularization

During 1970 to 1977, among 1,733 patients who underwent isolated coronary bypass grafting, the operative mortality was 2.5 percent. Actuarial 5 year survival is 88.1 percent. At an average follow-up of 46 months (range 13 to 108), 90 percent of patients remain angina-free or with symptomatic improvement. The 5 year survival rate of patients with single vessel coronary artery disease is 97.9 percent. In patients with multivessel disease, operative survival appears to be favorably influenced by the presence of normal preoperative ventricular function. Late survival is significantly better in patients with multivessel disease with normal preoperative ventricular function or with complete revascularization. Risk of perioperative myocardial infarction has been appreciably reduced by the introduction of cold potassium chloride cardioplegia. Late myocardial infarction has occurred at an average annual risk of 1.46 percent. These data show that long-term survival and a small incidence of late myocardial infarction after myocardial revascularization are more likely in patients who undergo complete revascularization before significant left ventricular myocardial damage has occurred.

Prophylactic coronary artery grafting in patients with few or no symptoms

Fifty-five patients who underwent prophylactic coronary artery grafting were followed for 4 to 8 years. Sixteen patients had no angina, and 39 were in New York Heart Association Functional Class I. Twenty-one patients had single-vessel disease, 13 had double-vessel disease, and 27, triple-vessel disease. A total of 101 grafts were inserted. There were no operative deaths. Two patients suffered a perioperative myocardial infarction (MI), and 3 were reoperated on for persistent bleeding. Early after operation, 9 of the 45 grafts were occluded. At 1 year, 2 patients had occlusion of all grafts, and 1 had similar findings at 5 years. There were 4 late deaths, 3 related to coronary artery disease. Seven patients sustained a late MI. Thirty-one of the 51 survivors (60.8%) seen late (mean, 69.3 months) after operation were free from angina; 14 were in Class I and 6, Class II. It is apparent from this retrospective study that patients such as these stand to benefit little from prophylactic revascularization. Longevity may be increased, however, in patients who are asymptomatic after MI.

An essential view in coronary arteriography

A significant stenosis of the left main coronary artery is associated with a significant mortality and is one of the major indications for aortocoronary bypass surgery. The diagnosis of this lesion on clinical grounds is inconsistent and should be established by angiography. All routine projections during coronary arteriography cause foreshortening of the left main coronary artery. Well-collimated anteroposterior and shallow right and left anterior oblique views show the main segment best. These views also show the proximal segments of circumflex and anterior descending branches, and should be routinely used during every coronary arteriogram.

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).