Public release of cardiac surgery outcomes data in New York: what do New York state cardiologists think of it?

BACKGROUND AND OBJECTIVE: Since 1990, risk-adjusted outcomes for patients undergoing coronary artery bypass graft surgery in New York state have been released to the public. The purpose of this study was to assess the extent to which referring cardiologists share these data with patients and use these data to make referrals. METHODS: A survey questionnaire was sent to all cardiologists in New York in the New York State Chapter of the American College of Cardiology. RESULTS: Four hundred fifty cardiologists responded to the survey. Most (94%) found the report "easy to read." A majority (67%) found the report to be "very accurate" or "somewhat accurate" in capturing differences in the performance of cardiac surgeons, whereas 33% found it to be "not at all accurate." Twenty-two percent reported that they "routinely discuss the reports with their patients," and 38% responded that the information has affected their referrals to surgeons "very much" or "somewhat." CONCLUSIONS: A majority of cardiologists has not generally changed their well-established referral patterns as a result of the New York coronary artery bypass graft surgery reports. However, there has been a modest impact on referrals resulting from the distribution of these reports. The findings also suggest that increased dialogue between clinicians and policy makers regarding the format and structure of public releases would be a valuable undertaking.

Public release of cardiac surgery outcomes data in New York: what do New York state cardiologists think of it?

BACKGROUND AND OBJECTIVE: Since 1990, risk-adjusted outcomes for patients undergoing coronary artery bypass graft surgery in New York state have been released to the public. The purpose of this study was to assess the extent to which referring cardiologists share these data with patients and use these data to make referrals. METHODS: A survey questionnaire was sent to all cardiologists in New York in the New York State Chapter of the American College of Cardiology. RESULTS: Four hundred fifty cardiologists responded to the survey. Most (94%) found the report "easy to read." A majority (67%) found the report to be "very accurate" or "somewhat accurate" in capturing differences in the performance of cardiac surgeons, whereas 33% found it to be "not at all accurate." Twenty-two percent reported that they "routinely discuss the reports with their patients," and 38% responded that the information has affected their referrals to surgeons "very much" or "somewhat." CONCLUSIONS: A majority of cardiologists has not generally changed their well-established referral patterns as a result of the New York coronary artery bypass graft surgery reports. However, there has been a modest impact on referrals resulting from the distribution of these reports. The findings also suggest that increased dialogue between clinicians and policy makers regarding the format and structure of public releases would be a valuable undertaking.

Hemodynamic and regional blood flow response to milrinone in patients with severe congestive heart failure: a dose-ranging study.

This study was undertaken to assess the hemodynamic efficacy, changes in regional blood flow, and safety of milrinone over a range of intravenous bolus injections (12.5 to 125 micrograms/kg), a continuous 18-hour infusion (0.2 to 0.7 microgram/kg/min), and following oral administration. All eighteen patients with New York Heart Association class III or IV congestive heart failure demonstrated hemodynamic improvement following intravenous bolus therapy. Dose-related increases in cardiac index occurred, ranging from a 12 +/- 6% increase following a 12.5 micrograms/kg bolus to a 37 +/- 10% increase after 75 micrograms/kg. Pulmonary wedge pressure fell 17 +/- 5% following 12.5 micrograms/kg and 28 +/- 9% following 75 micrograms/kg. Little change was apparent during the continuous infusion except for a late increase in cardiac index, but similar changes occurred in response to a single oral dose. Forearm blood flow increased significantly after 3 hours in the two higher infusion groups, but there was no consistent change in hepatic blood flow. We conclude that hemodynamic parameters and forearm blood flow are improved in patients with severe congestive heart failure following intravenous and short-term oral milrinone therapy.

Comparison of intravenous milrinone and dobutamine for congestive heart failure secondary to either ischemic or dilated cardiomyopathy.

Milrinone and dobutamine are positive inotropic agents with beneficial hemodynamic effects in patients with congestive heart failure. This study was undertaken to compare the effects of intravenous milrinone and dobutamine in patients with stable New York Heart Association class III or IV congestive heart failure and to test the hypothesis that intravenous milrinone is at least as beneficial as dobutamine in this setting. Seventy-nine patients were randomized to either dobutamine therapy at incremental doses of 2.5, 5, 7.5, 10, 12.5 and 15 micrograms/kg/min, or milrinone as a bolus of 50 or 75 micrograms/kg followed by an infusion of 0.5 to 1.0 micrograms/kg/min. Both agents significantly increased heart rate, cardiac index and stroke volume index and decreased pulmonary artery wedge pressure and systemic vascular resistance compared with baseline levels (p less than 0.01). During sustained infusion for 48 hours, no difference in hemodynamic effects was observed between the 2 drugs. Ventricular tachycardia occurred in 5 patients (3 taking milrinone, 2 taking dobutamine); 1 patient taking milrinone had ventricular fibrillation. Milrinone and dobutamine elicited similar beneficial hemodynamic results with relatively few adverse effects.

Vigorous supplementation of a hypocaloric diet prevents cardiac arrhythmias and mineral depletion.

We have previously demonstrated that a hypocaloric, nutritionally deficient, liquid protein diet is associated with potentially life-threatening cardiac arrhythmias, which increased in frequency and complexity over the duration of the study. The present investigation was designed to evaluate the metabolic and cardiac changes associated with a hypocaloric, but otherwise nutritionally complete, diet. Six healthy, obese females from 154 to 182 percent of ideal body weight were evaluated in a metabolic ward for 48 days. The subjects ingested a weight maintenance diet during an eight-day period, which was followed by 40 days of an experimental diet containing 472 kcal of a mixture of protein (60 percent of calories), carbohydrate (25 percent), and fat (15 percent). This diet equaled or exceeded the recommended daily allowances for minerals, trace elements, vitamins, and essential fatty acids. The subjects were monitored for balances of nitrogen and minerals, as well as for the appearance of cardiac arrhythmias by 24-hour electrocardiographic recordings. Nitrogen balance was positive, and the previously demonstrated negative balances for potassium, sodium, calcium, magnesium, and phosphorus were either reversed or markedly decreased. In contrast to our previous study, no arrhythmias were observed in subjects ingesting the present experimental diet, and no significant change in cardiac rhythm was found in 13 obese, but otherwise healthy, outpatients. The data, based on a limited number of subjects, suggest that a hypocaloric diet vigorously supplemented with essential elements, micronutrients, and vitamins appears to be safer than the once popular, incomplete liquid protein preparation.

Comparison of the effects of dopamine, hydralazine, and isosorbide dinitrate on myocardial hemodynamics in patients with refractory heart failure.

Nine patients with refractory congestive heart failure underwent hemodynamic study first with dopamine and then with oral hydralazine and sublingual isosorbide dinitrate. Although hemodynamic improvement was achieved with both forms of therapy, the beneficial effects of hydralazine alone or with isosorbide were superior to those of dopamine, as manifested by a greater reduction of wedge pressure and greater increase in stroke index. Six patients who demonstrated an increased wedge pressure during dopamine infusion were observed to manifest a louder apical systolic murmur and/or V wave in the wedge pressure tracing suggestive of enhanced mitral regurgitation. The rise in wedge pressure on dopamine could also be a consequence of increased myocardial ischemia and resultant decrease in ventricular compliance. It is possible that a subgroup of patients with heart failure are made worse by dopamine, and in these cases vasodilator therapy may be more beneficial.

Clinical evaluation of a radiometric assay specific for creatine kinase isoenzyme MB.

A new radiometric assay specific for creatine kinase isoenzyme MB was evaluated with respect to its precision and agreement with a conventional electrophoretic CK-MB assay for the diagnosis of myocardial infarction. The reference interval we find for serum CK-MB in healthy subjects is 0--30 micrograms/L. The coefficients of variation at 197 and 40 micrograms of CK-MB per liter, were 5.2 and 11.5%, respectively. In a clinical study of 52 consecutive patients admitted into a Coronary Care Unit with a diagnosis of suspected myocardial infarction, there was overall agreement in CK-MB results by the two assays for 51 of 52 patients. A more sensitive and quantitative assay that is specific for CK-MB can be helpful in cases where diagnosis of myocardial infarction is equivocal.

Effect of furosemide on hemodynamics and lung water in acute pulmonary edema secondary to myocardial infarction.

Hemodynamic studies were carried out in 19 patients with left ventricular failure complicating acute myocardial infarction. Fourteen patients were studied before and after the intravenous administration of 0.5 mg/kg of furosemide, and five patients served as a control group. Serial measurements included intracardiac pressures, cardiac output and lung water by a double isotope technique. A significant reduction was noted in right atrial (P less than 0.005), pulmonary arterial (P less than 0.0005) and pulmonary wedge pressures (P less than 0.0005) after administration of furosemide. Only the change in right atrial pressure was significantly different from that in the control group (P less than 0.05). Lung water was not changed in 4 patients studied 2 hours after administration of furosemide but was significantly changed in the remaining 10 patients studied 4 to 24 hours after furosemide (P = 0.0001). This change was also significantly different from values in the control group (P less than 0.05). The patients with no reduction in excess lung water also had a smaller reduction in pulmonary wedge pressure and a lower pretreatment stroke work index than the other patients. The mobilization of excess lung water in patients with acute myocardial infarction complicated by left ventricular failure has several features. Despite a prompt diuresis, the reduction in lung water is delayed for at least several hours after the administration of furosemide and may be related to the degree of left ventricular dysfunction. Venodilation may be a major result of treatment with furosemide.

Relationship of serum and myocardial digoxin concentration to electrocardiographic estimation of digoxin intoxication.

Serum and myocardial digoxin levels were studied in 18 patients who came to autopsy. An independent analysis of electrocardiograms prior to death was made to ascertain the relationship between serum and tissue levels of digoxin and clinical estimation of drug toxicity. Patients with arrhythmias of digoxin toxicity had higher mean serum and tissue digoxin levels than patients without arrhythmia. There was overlap in the patient groups, however, and the differences were not statistically significant. The tissue to serum ratio was lower in the toxic patients. The latter phenomenon is unexplained but may be related to decreased tissue binding.

The hemodynamic response to intra-aortic balloon counterpulsation in patients with cardiogenic shock complicating acute myocardial infarction.

Sixteen patients with cardiogenic shock complicating acute myocardial infarction underwent serial hemodynamic studies during intra-aortic balloon counterpulsation (IABC) at an assist frequency of 1:1. Significant increase was noted during the first 12 hours of IABC in the systemic artery peak diastolic pressure (assisted), cardiac index, stroke index, and stroke work index. During the second 12 hours further significant improvement was noted in the latter three parameters and, in addition, the systemic artery systolic pressure increased significantly. The pulmonary wedge pressure fell as did the total systemic resistance (TSR) during the first 24 hours of IABC. Patients found to be balloon independent after reduction in balloon assist frequency demonstrated significantly greater increase in systemic artery peak diastolic pressure during the first 12 hours of IABC than did those patients found to be balloon dependent. Likewise, the improvement noted in CI, SI, and SWI during the second 12 hours of IABC was of greater magnitude in balloon-independent than in balloon-dependent patients. The data suggest late hemodynamic deterioration after 48 hours of IABC. It is concluded that IABC is effective in improving the deranged hemodynamics of cardiogenic shock. Maximum response is noted between 24 and 48 hours. It is suggested that patients who are balloon independent may be distinguished from those who are balloon dependent by the hemodynamic response within the first 24 hours of IABC.

Hypoxemia and lung water in acute myocardial infarction.

Pulmonary extravascular volume or lung water (PEV), arterial blood gases, and cardiac hemodynamics were measured in 88 patients with acute myocardial infarction. A progressive increase in PEV and a decrease in arterial oxygen tension (PaO2) were observed from Class I (uncomplicated) patients to Class III (frank pulmonary edema) patients. Heart rate and pulmonary wedge pressure (Pw) rose and cardiac index declined with increasing severity of heart failure by clinical classification. There was a significant correlation between PEV and Pw independent of clinical class (r = 0.47, p less than 0.01). PaO2 had a negative correlation with Pw (r = -0.28, p less than 0.01) as well as PEV (r = -0.26, p less than 0.02). We conclude therefore that increased pulmonary hydrostatic pressure secondary to pulmonary venous hypertension in patients with acute myocardial infarction is a major determinant of interstitial edema. At higher values of PEV, PaO2 was lower. The mechanism of hypoxemia in the presence of excessive lung water may be due to multiple factors, including small airway dysfunction and intrapulmonary shunting.

Dissection of the aorta complicating intra-aortic balloon counterpulsation.

A 61-year-old man with recent myocardial infarction complicated by a ventricular aneurysm and recurrent ventricular tachycardia underwent intra-aortic balloon counterpulsation prior to angiography and left ventricular aneurysmectomy. A dissecting aneurysm of the descending aorta adjacent to the position of the balloon catheter was found at autopsy. No intimal tear or cystic medial degeneration of the aorta was present to account for the dissection. The authors suggest that lateral and shearing forces generated by inflation of the balloon could result in dissection of the aorta.

ST-segment variations after acute myocardial infarction. Relationship to clinical status.

The degree of vectorcardiographic ST-segment elevation was employed as an index of myocardial ischemic injury in a study of 27 patients after acute myocardial infarction (AMI). The ST-segment vector magnitude (STVM) was derived from the continuously recorded modified Frank vectorcardiogram and was plotted serially by hours after onset of AMI. The STVM in normal subjects was 51.1 +/- 7.1 muV (mean +/- SE). A standard deviation of the pooled variance of 15.2 muV was obtained in a group of control patients and a change of more than 2 SD (greater than 30 muV) in an individual STVM was considered to be significant. The STVM progressively decreased in patients who survived without clinical complications while it remained elevated in those with congestive heart failure. A modest, sustained re-elevation of STVM was observed in patients who developed pericarditis, and a significant late average increase of 64 muV occurred in survivors with infarct extension. In contrast, STVM underwent a major increase in patients who died. In five of these six patients without associated pericarditis a mean increase of 164 muV was recorded in the last 5-12 hours of life. While death was clinically predictable in two patients with cardiogenic shock, it was not so for the four other patients who died. Thus, major increases in STVM frequently suggested significant new ischemic injury and were often premonitory to sudden death after AMI. The increases preceding death implied that not only ventricular extopy but also lethal conduction abnormalities after AMI might be ischemia-related.

Ventricular arrhythmias and cardiac hemodynamics in patients with myocardial infarction. Comparison of the acute and post-hospitalization phases.

Sixty-six patients with myocardial infarction (MI) were studied during the acute hospital phase and during the six months after hospital discharge. The clinical characteristics, location of infarction, and data from right heart catheterization were studied in an attempt to determine what factors were associated with ventricular rhythm disturbance. Those patients with serious ventricular arrhythmias (SVA) in the acute phase of infarction were found to have a significantly greater degree of myocardial dysfunction as measured by pulmonary artery and pulmonary wedge pressure than patients with more normal rhythm (p less than .05). Clinical classification of patients and location of infarction were not helpful in predicting SVA during the acute infarction period. Knowledge of hemodynamic data, presence of SVA and clinical characteristics in the acute infarction period were of no value in predicting the occurrence of SVA after hospital discharge patients having had an acute diaphragmatic infarction were found to have a higher incidence of SVA after hospital discharge.